To add my opinion to the above: I love Hue bulbs, and I love the Hue ecosystem. Hue bulbs produce exellent whites and colors (again, not gen 1-2), and they have a variety of accessories that can work directly with the Hue system for manual control of lights (Hue Dimmer, Hue Tap, and various "Friends of Hue" products like the Lutron Aurora and RunLessWire Click) or control via voice (native Alexa and GH support) and other platforms (official HomeKit/Siri integration plus a well documented local API that platforms like Hubitat use to integrate with lights). Sengleds can be found for cheap, but I don't like any of their whites except the warm white (they're fine for that and color--but if you have a lot you'll also need to make sure you have enough Zigbee repeaters since these count towards your end-device limits). As noted above, most others are a bad idea to pair directly to Hubitat since they are poor repeaters and may cause problems unless they're the only kind of Zigbee device on your network.
As much as I love Hubitat--and have, in fact, purchased a second (OK, fourth) hub to experiment with running Zigbee smart bulbs only--I agree with that if you only plan on using Hue, a Hue Bridge is a lot easier to set up. It's designed only for lighting and makes adding and managing lights and groups/rooms/zones a breeze, plus it supports "true" Zigbee scenes and can automatically add common default scenes for you (Read" = 3000K at 100%, "Concentrate" = 4000K at 100%, "Relax" = 2250K at 67% or something like that). Hubitat can discover the Bridge and devices on that network. HubConnect is great but a bit more work, and I honestly haven't found Hubitat great at manipulating lots of Zigbee bulbs at once except via group messaging (which can't help if each bulb in a scene is different; Hue can store these on the bulb, so it's instant and reliable to switch to a Hue scene). And you still don't get all of the above benefits--e.g., if you want Siri support, you'll have to set up a HomeBridge server.
That being said, Hue will cost you. You may be tempted to save money by using third-party compatible bulbs. Ikea Tradfri and Eria are both compatible, but you'll lose some of the above benefits. No third-party bulb supports Hue's power loss default state feature, and they are excluded from Siri/HomeKit, for example. Ikea bulbs are also very slow to respond to color changes (but I do confess that I like their "shades of white" bulb better than the Hue White Ambiance--it's brigher and has better light distribution, though it only supports three specific color temperatures). I haven't used the Eria so can't speak for it. I've used Cree Connected soft white and daylight bulbs, and both work well aside from not supporting the above.
Basically, it comes down to what features you want and what you're willing to pay. I like Hue, but if you don't go down that path first, maybe you won't miss what you don't know about, like a 2250K color temperature the Sengled strip can't quite trick my picky eyes into believing is warm enough.
Just to note...any of the control methods you mentioned, if they take place outside of HE, there will be delay in HE knowing about that change. So, if you're using a hue tap to turn on lights and you also want that to trigger lights connected to HE, there will be a delay between that happening. From 10 seconds up to 5 minutes if you don't have the polling set correctly. But the lowest setting is 10 seconds. And if you have a lot of Hue bulbs that is going to put a strain on your lan and can still cause a 10 second delay.
That makes sense from a technical perspective. Being that I previously have not owned any smart bulbs I've wondered how the always-on requirement works in practice. Home light fixtures are almost always switch controlled which would mean for a smart bulb you would have to always leave the switch in the on position. If someone forgets or accidentally flips the switch off then guess what, no more smart bulb.
From what you said then I take it smart bulbs have no memory of what their last color setting was? I guess if I really want to control color then best bet would be to replace X-10 switch with a standard switch, leave powered on and install smart bulbs? In that configuration it seems as if you would lose the easy manual override switching to turn on the light (would be an off and then back on again of the manual switch to reset and turn on the smart bulb, correct)
They do have a memory...but only while power is still applied. The one exception being Hue but only when paired to a Hue hub.
You can also use one of the "over switch" solution like theLutron Aurora device which fits right over your toggle switch.
All bulbs with have a default "on" setting. For example, the sengled is Medium warm white, 100%. If you remove then re-apply power to the bulb, that is the level it comes on to.
Just a thought also to remember that there are other cheaper zigbee lamps you can add to and control with a Hue hub. So you get the benefits of Hue control with somewhat reduced cost. For example, the Gledopto range (just search for them in AliExpress). So the options go beyond "to Hue or not to Hue", as it were
My sylvania lights remember their last color temp and level if turned off at the switch. They only revert to 2700K and 100% if they are reset. Granted, they do come on to their last "on state" when power is restored, which is why only Hue lights are in the bedroom (plus the Hue's dim much lower).
I can't remember if they behaved this well before updating. Whenever I get a new one, the first thing I do is join it to SmartThings and update the firmware since like seemingly everything, they come brand new with the original firmware version that is buggy as heck.
There was discussion above about the merits of Hue but the downside of cost. My post was addressing this. You can have the (many) benefits of a Hue based lighting system at a reduced cost by linking other lower cost ZLL lamps to the Hue hub. Personally, I think Hue is brilliant. It's completely robust. It isolates the lighting system reducing load and potential conflict on the HE hub. It enables the new Sync functionality. But it pains me to pay 40 bucks a lamp. Hence my post about using Gledopto instead, as an example.
Ah, tired now from all this explanation. Interacting on this forum really is tough sometimes.
Do keep in mind that this still keeps you out of a couple things--default power-on state, for example, is only supported on Hue bulbs (I don't think Philips is being intentionally limiting here, by the way; I'm pretty sure it's a special feature baked into newer firmware, and it definitely did require a firmware update to work). HomeKit/Siri support is also not there for third-party bulbs (again not sure this is Philips; probably some Apple requirement, and if you have HomeBridge you can still get there via Hubitat).
I've ended up replacing almost all of my non-Hue bulbs with Hue, with one exception being the cool white Cree Connected (I wish Philips made something similar, and an Ambiance would get there with a bit more cost if you set it to default to cool) and formerly an Ikea Trådfri "shades of white" bulb (much brighter than any Hue bulb and with a bit better light distribution, but limited to three exact color temperatures, luckily the only ones I'd really use anyway; and the slowness isn't as apparent with these as with the Trådfri color bulbs).
However, you'd be in basically the same spot if you used a second Hubitat, so no big loss either way. (And again, I agree that Hue is a lot easier to set up if you'd only use the second hub for lighting purposes, as much as I'd like to see more Hubitats sold. It's also incredibly reliable--most Hue-to-Hue things like a Dimmer turning on a scene can be done without the Bridge at all, but ZHA would need the hub for almost everything.)
I agree Hue is good have one myself. Not arguing that. Not really trying to argue at all actually, so I apologize if I seem argumentative. But @mike.maxwell made a good point that HE doesn’t limit you to just ZLL and he uses a mix of ZLL and HA bulbs on his second hub.
If I needed more bulbs and wasn’t already invested in Hue and TRÅDFRI, I would probably do the same type of setup.
Okay....what ZHA bulbs would you want to use? Sengled are non-repeaters so can join to your HE no problem. Osram? Definitely would avoid those. I can't think of any other bulbs that aren't ZLL.
I don't have a lot of experience with other bulbs. I know that there are others. They are not on the compatible devices list, but may be that they simply have not been tested, no other reason.
If I were to build a new home as an example, there might be certain bulb types that suit my needs perfectly. What ever it takes and makes my wife happy, you know?
I just prefer options, especially those that might help Hubitat. This is an excellent hub and I really like the platform, and I want them to sell units. I know of nothing else they sell but hubs, and accessories to the hub. I would not have such an excellent and reliable home automation system without it. So I have no qualms in promoting its continued growth.
Aurora have ZigBee 3.0 lamps out and are currently sending their range to HE so that's another + for using a HE hub. Although I have been told that they repeat well by one of their guys who has them in his house as the repeaters.
So can we say point goes to a second Hubitat Elevation hub here? 
(And again, I agree that Hue is a lot easier to set up if you'd only use the second hub for lighting purposes, as much as I'd like to see more Hubitats sold. It's also incredibly reliable--most Hue-to-Hue things like a Dimmer turning on a scene can be done without the Bridge at all, but ZHA would need the hub for almost everything.)
