We recently migrated from on-premise to cloud and it was the best decision we made. We use to get so many issue with every upgrade which we don't anymore. Profiles and policies work seamlessly. We do get some issue but this is resolved fairly quickly.
I would highly recommend you migrate now as on premise setup will be phased out eventually.
Its really down to your business needs. We migrated to cloud in August, so far I have no regrets.
Dont listen to the sales pitch about not needing to reenroll devices. Our servers URL was not publicly resolvable, and we were told many times that was not going to be an issue despite my statements that it would be an issue. Well, it was an issue. The sales team has no idea what they are talking about and will not put you in touch with an engineer until after money has exchanged hands. That is the biggest negative I have as a takeaway.
As far as use of the product. We have not seen an issue since our migration in August. Not having to maintain the on prem servers, or the SSL certificates has been a massive deal. JAMF Cloud also has features that JAMF limits in JAMF Pro (On Prem), some of those features are really useful. Really, it's down to this question. Do you want to keep maintaining the on prem servers or do you want to hand that off?
In the event JAMF does go down, with it being hosted, literally all you can do is report the issue. There is no digging around on the server to figure out what broke and how to fix it. That is on JAMF to sort out.
Hardware isn't too big of an issue since you can run VMs in Linux but the actual set up can be a pain in the butt depending on your security posture. For me, I have noticed that JAMF Cloud just works better and seems to handle MDM commands better than any of my on-prem environments. Im in an on-prem environment right now and it just doesn't work as well even though its a well laid out environment.