Ahh, I am not against wireless alarm systems which of course embrace the retrofit solution. I am against DIY wireless HA systems implementing alarm systems.
I would far prefer a low cost ‘recognised’ standalone wireless alarm system that has an integration with HE. That way it works 100% dependably and independently no matter what you do with HE.
Do look at Home Assistant too - it has a load of device support available and is flourishing in enhancements on a regular basis currently. Most of HomeSeers plugins have HA equivalents.
Yes it has a bit of a learning curve and YAML is horrid but I recommend it.
My enthusiasm waned a little bit with Hubitat recently but just now they seem to be on a roll again, so I’m a happy bunny once more, a few niggles still to iron out but I wouldn’t be without it. Glad you’re enjoying it.
I use HA, and HomeSeer actually to add integrations (typically cloud) that HE doesn’t yet have, usually linked to HE over MQTT. You might not wish to dabble quite so much but it’s all doable !
What version of HomeSeer are you referring to in regards to the GUI sucking? But lets just be serious with ourselves the Hubitat GUI isn't a real winner and without the dashboard addition you can't get a device status without clicking into each and everyone individually. But I'm not here to be a fanboy of any system. We each use what works best for us.
HomeSeer has NO Zigbee support. It's only provided by plugins and yes deCONZ has helped that area A LOT. The new Hubitat Plugin makes it much better... unless you think Hubitat Zigbee sucks? 
I ran HS3 Pro, but stopped about a year and a half ago as I wanted/needed options for zigbee - so maybe the UI has improved since then. And I don't think Hubitat's interface is great either from a usability standpoint - so I'm certainly not holding it up as the model of 'good' either. 
In fact, I will say I really LIKED the plugin summary and management screens on Homeseer.
It is good that there are integration plugins in Homeseer - it needs it. For my use, though, even though I own an HS3 Pro license there is simply no need to use Homeseer versus Hubitat. There really isn't anything I can't do in Hubitat that I could do in Homeseer - again, for MY uses - and no PC and heavy overhead to maintain anymore using Hubitat.
As I was going through my home IT simplification process, I was able to get rid of every server and RPi I had running in my house. Don't need them any more. I have a good NAS for storage, can spin up ad hoc VMs as needed for development, but I have no server maintenance/overhead at all. zero. And it is lovely, because while I support enterprise architecture at work - I certainly don't want to spend my time doing that at home.
... and that's the key difference between Hubitat and any of the other options mentioned here
@jeubanks - whilst you're around - you seen the new integrated MQTT client in Hubitat ?
It's working well ...
That's what really killed my interest. It just wasn't the cost.
Mass reply 
@JasonJoel then we agree... the HS3 Web UI is not great by any means but I've seen/used far worse. I can say it is functional and it is "utilitarian" at best. HST is doing a revamp (currently) and there is an update coming at the request from EVERYNONE so you are not alone with the view of the "Old" style UI but it gets the job done and if you want better there are options and HSTouch which is a PITA but you can make some awesome screens.
The no pc running... well everything is a PC running these days whether it's the hub or a rPi or a little mini server running something. Maintenance I think is the key here. I run HS3 on linux which I'm comfortable with. So maintenance for me is very minimal really. I don't port forward I use the MyHS service for outside access so I'm good. Again there's the pro/con aspect of does the hardware match your requirements... it's all a give/take of each individual and environment requirements and wants. No argument from me there.
For me HomeSeer is the "Controller of Controllers". I have various systems that I need to tie together. Not one of them can do all of it. HomeSeer is "my glue" for things. HS doesn't have Zigbee but Hubitat has great Zigbee... so I glued them together. I have ISY and HomeSeer has an integration for that too. I have Insteon and I can do that direct or through the ISY or Insteon Hub either way. Like you said it's all about the individuals requirements and needs.
Short of it is not everyone "needs" HomeSeer... nor will they want it really it is complex because it can do so much which is why there's a high cost to it and why there are integration companies that work with it. Want HomeSeer? Call us we'll gladly sell you a system and do integration work costs a lot!
@kevin - I did see the new mqtt client... I was a little excited about it. I'm hoping to get some time soon to start playing with it.
Simplification has been a big one for me to. However, I’m still running an esxi host with a few vms.
I’m getting closer.
Okay I'll fess up... One of my retired Xeon servers is still in the closet... Just in case I need to spin up proxmox for some VMs... But it's not powered up... I promise!
That's ok... nobody is judging
My Blue-Iris server is larger/more powerful than my HS3 server so... That Blue-Iris is something I'm looking to eliminate... Xeoma is nice and runs on a rPi very well so I may write a plugin for that Or drop the big $$ and go all Unifi setup and then get the Unifi plugin 
When I removed blue Iris I coughed up the licenses to bring my cameras to my Synology NAS.
Not as many features, but works pretty well, and was convenient since I wanted a standalone NAS anyway.
There’s enough power to run your cameras off that?
I may have to consider that option....
Sometimes this forum truly makes me laugh.....
The big advantage that I have found with Surveillance Station is that it will generate a MJPEG stream which is then picked up by my SharpTools dashboard.
The only reason I would use camera on my Home automation setup ( Homeseer)
would be for the ability to process/detect/recognize people locally, for occupancy ( without cloud). I guess i will wait a long time.
1-3 cams outside the house at low fps is enough for me ( for recording).
can hubitat control synology surveillance station profiles (armed/disarmed) state? from this thread it seems like it can?
You might post a separate question (new post) on this, it may/may not work with something like MakerAPI integration, I don't know as I'm not smart enough to know how to use it, but someone here would definitely know for sure many do use that integration. Otherwise they would point you to the right direction if it's possible.
EDIT
Just realized you meant change the mode on Syno not change the Hubitat mode, not sure that can be done.
As a blue Iris to Synology convert while I haven't done this exact thing but it absolutely can be done, simply alter the end points of the tutorial I put together using Surveillance Studio to activate a virtual motion sensor...
Cheers.
Download the Hubitat app
