I would say you need to look from a higher point of view. Those desktops needs to be accessed as well and thus endpoints come into play. Suddenly you are looking at UEM/MAM and have to wonder if you want to stitch solutions together or have one vendor. make sure all your endpoints can be managed and protected.. not just a part of them..
(mind you, I work for VMware... just, so you know)
but back to VDI/DaaS... most important is the Day2,3...100 functionality a solution has.
Topics I would focus on are:
1. Profile management (besides dumping it with fslogix)
2. Image management (fewer images is better)
3. App deployment (on-demand instead of hug images or at-logon)
4. User environment management (GPO's are of the 90s) on-demand, context-based personalized desktops.
5. security and compliance (keylogger, watermarking, screen scraping, quarantine, endpoint protection, network segmentation)
6. Hybrid deployment for when the shit hits the fan (Azure/AWS-only is not going to work)
...again, I work for VMware so, yes a bit biased of course.. happy to go into details about Horizon if you like but just wanted to give some day 2 thoughts for you (been in the field for ages myself)