The trap is you need Microsoft support training & strategy. If you buy unified and open a sev a, they just fuck around and assign an engineer from Antartica who works from 3AM-6:20AM Mongolian time, then reassign at 6:19AM to dude in Japan to reset their 2 hour SLA for the incident manager. In general, if you are big, you're better off buying Premier from a partner, and declaring a crit sit. Many issues are fixable by less dumb third party L2 techs, and you can leverage the partner's juice with Microsoft to get somebody. You have the ability to inflict real pain on the reseller, but all Microsoft will do for a strategic customer is send some VP of something to apologize profusely at great length and suggest the more staff meet with your TAM/CSM so they can get a dramatic reading of a powerpoint. Companies like this only understand pain, so you need leverage.
Microsoft is uniquely bad at this type of stuff. Anyone committing serious infrastructure where bad things are gonna happen when it goes down is insane for using HyperV. But you're also insane expecting a small reseller of some small company to pull your chestnuts out of the fire.
With open source, if you have the right people, you can find/ bisect down to the commit and function where the problem is exactly, which speeds up the remedy immensely. We have done such a thing with backup restores from the Proxmox Backup Server. The patches are now in Proxmox VE 9.0 because the low hanging fruit problem was actually with the client code not the Proxmox Backup Server.
The show stopper is explaining to your CEO that you don’t have 24/7 support on a piece of software that’s core to the business.
You can explain away horrible 24/7 support and keep your job. Not so much if you buy something that doesn’t even offer it and you have a hard outage at 5pm on a Friday.