single floor or multiple floors?
I get great coverage with 3. I had to add the third in my front attached garage to get better coverage out front of my house.
as well as 1 in the main floor living room and 1 in the basement.
House is stucco exterior as well which probably doesn't help for outside.
Correct, but the Nano HD is not built for distance, that's what the LR line is for. Even with the "Long Range" APs Unifi still falls short on the hardware side. I have said it before UBNT is a software 1st network, not hardware, always has been.
FYI "out of the box" a Nano (and most all Unifi APs) will top out at 400Mbps. You need to go into the controller software and change the channel width to VHT80 in order to get 866MBps. Not a big deal if you know it, but if you don't....
Do I love Unifi, yes. Does it need some work, absolutely. For now I would (and do) run an Untangled firewall/router (or Pfsense, Fortinet , Edge, ASUS or another router) and leave UBNT for the 'networking' side of things. Unless you only need basic routing, no reliable Geo-filtering porting/firewall routing, and under 800MBps connection, for that Unifi is great. Granted for most homes and small businesses this is all you/they need, so great (well good, not great). I have another UDM+switch+2x APs next week. They will love it. I need just a touch more routing, and a lot more reporting for my LAN.
The Wi-Fi 6 "Lite" APs are available via early access, and I would not buy Wi-Fi 5 at this point (things in IT never stop moving forward no sense buying old tech). The "Lite" APs work just as well as Nano's coverage wise, they lack the VHT160 band, but its rarely used. Yesterday I set a HD Nano next to a W6 Lite and did some RSSI test, nearly identical FWTW.
I noticed the WiFi 5 Unifi APs include options that support 4x4 mu-mimo, whereas the WiFi 6 Unifi Lite AP in the early access store is 2x2 only.
In a home environment with a few 802.11ax clients, do you think that’s much of a limiting factor?
Sorry, I always say "ranch" as if that means the same thing to everyone...single story. 
I don't do any wi-fi in the garage so I've never even checked for coverage out there, given the Farady cage-like properties of all the junk in the garage I would not be surprised if I don't have great coverage there w/one device. (My smoke alarm, water cop water valve, and leak sensors do connect and work fine from there.)
My home is late 60's standard wallboard/wood studs construction, combination of stucco and wood siding. One example of how good my coverage is - outside one of the rear corners of my home on the outdoor patio, (sitting comfortably on a chaise lounge of course 
) I can get 150+. My theoretical max set by ISP is about 230-240 IRRC. That's pretty darn good and of course covers anything I'd ever want to do out there.
I'm not dealing w/basements of course, so your setup is more troublesome than mine in that regard. We don't do basements out here in decomposed granite ground/earthquake country. Too hard to dig, and too likely to fall into our own hole. 
I'm pretty happy with my Unifi setup. The USG does leave a little to desire, especially on the throughput front, but the switches and APs have been rock solid in my experience. 2 NanoHDs and an In Wall HD covers all interior spaces (3800 sq ft 2 story w/ basement) with 5G VHT80.
The only place I feel like I'm lacking a bit is the garage where 2G is fine, but 5G just isn't making it. That's probably due to the footprint of the home. While attached, the garage is sitting on a slab adjacent to the actual house. Have been thinking about adding a FlexHD out there... just because I hate 5G capable devices being reduced to 2G peasantry. 
That means I'd have to drill through concrete to get a cable out there though so that might be on permanent back burner. 
OFDMA should make up for the missing MU-MIMO streams. If you are not familiar with OFDMA check out this quick video, he does a decent job of explaining the basics of "car pooling". Of course I'd rather have 4x4 MU-MIMO, so you could try waiting for the "sold out" LR or Mesh units. I've been on the email list for a few weeks with 0 updates on stock. I finally broke down and got the Lite for testing/use
If your internet is not over 200Mbps it may matter very little in the end. To save yourself the wiring hassle put a beacon in the garage, or just inside the house next to the garage, it should add 5G in there.
You're absolutely right and, while my down speed is a theoretical 700 MB*, my up is much MUCH lower and that's mostly what the devices out there utilize. That upgrade is definitely low on the priority list.
*I don't have Threat Managment enabled on the USG
I recently converted my home network over to Ubiquiti UDM base, along with three UniFi AP’s (NanoHD, FlexHD, and an AClite), and multiple UniFi POE switches. Our home network has never been more stable... and I had a good time designing and building it out.
I do believe it is important to find a stable firmware version and stick with it for a while. Don’t try chasing the latest UniFi releases.
I feel like this advise can be given for a lot of products... 
looks at address bar 
I've written about my Love of Ubiquiti many times on these Forums.
While there are quirks. I'm using an Er-lite router, 3 WAPs (1 AC HD, and 2 AC Pros) An 8 Port PoE lite Switch, a 16 Port Lite Switch, a boatload of 5 port Flex switches, 3 G3 Pro Cameras, G3 Flex Camera, the new Doorbell, and Cloud Key Gen 2.
My network is stable, reliable, and just works.
BUT, I'm broke, and WiFi 6 is going to be costly when I transition.
S.
I run UniFi APs. Love ‘em.
Firewall? pfSense for sure.
I’m a bit biased.
Every time I've tried Ubiquiti it can't seem to keep up and the CPU gets saturated. The Cisco gear chugs along just fine though.
Having just skimmed through this thread here, so this may have already been pointed out. The UDM Pro was certainly quite buggy at launch. However since beta firmware 1.7 and now stable firmware 1.8 it's been absolutely rock solid for me. Zero issues.
As someone starting down the Ubiquity path, I'd consider a UXG (would never give a USG a second look at this point). But I'd likely still end up with a UDM pro. The value is just too good vs buying individual components. All the features of a USG, cloud key, 8 port switch and if you ever want to spend a fortune on their overpriced cameras it has the NVR as well. It is by far the best bang for the buck right now.
I have a UDM Pro, US-16-XG, US-48 and 3 AP's. With IPS enabled with full protection and DPI enabled as well, I can easily pull 1,480mbps. The USG Pro 4 caps out at 250mbps.
Oh, and did I mention the UDM Pro can also run docker containers? I've got mine running AdGuard at the moment, but it can also run home assistant, node red or pretty much anything that can be run in docker.
UDM..
I do have a (not currently used) UDMP Pro so I am glad to hear it's a lot better now... It's definitely a great value product.
Unfortunately you can't easily add 'parts' of its capabilities into an existing network (something I had hoped you could when I acquired it) so it isn't useful to me and I haven't kept up with it's firmware updates. It's back in its box whilst I think this through...
As a single box solution for home users I think it's positioning is undeniable and it's router performance is fast.. If 1.8 is solid now then I would definitely consider it..
Is there any way I could share my incoming WAN between a UDMPro and a USG Pro ? Two separate but routable to each other networks would be fine.
I'll just ask here instead of making another thread. Can the USG be made to route to specific IPs/MAC only when say WAN1 is down and WAN2 kicks in during failover?
I'm trying to prevent streaming when the LTE connection is on.
Thanks to a nudge from @ogiewon I recently jumped down the Unifi rabbit hole. The hole is 2 fold....one for the rabbit and the other for your wallet.
I got the UDM pro, which does have it "quirks" but has been very stable for me. I added 2 FlexHD AP's and an AC Mesh for my garage. I recently swapped out my Netgear POE switch for a Unifi Switch 8 and added a G4 Bullet, a G3Flex and a G4 Doorbell.
I love the flexibility of configuration options available especially with regard to POE.
Also with the UDMPro, I'm able to maintain a 1gig internet connection even with Deep Packet Inspection and Threat Detection on with no loss in speed at all.
All that being said I'm most happy with the G4 doorbell that replaced my Ring doorbell. MUCH better video quality, load times and consistent detection.
I'm new to unifi but VERY happy at the moment.
I am trying for weeks to get a hold of one. Always sold out even with email notification 
I never got an email notification of stock and just checked daily (refreshed browser tab on my phone). When it popped up, I bought immediately and it sold out the same day.
I love how people in the UniFi forums defend this decision by saying “this is enterprise grade hardware, and any enterprise will have a dedicated logging solution”
Meanwhile the hardware I used to route and switch my own public /22 had logs
Someone please correct me if I'm wrong, but I seem to remember the UDMPro is not a POE switch.
Download the Hubitat app
