I have IP Office application servers running on a wide variety of sub-$200 small form factor servers. Haven't had any fail yet and the oldest is about 5/6 years now. From the technical view-point thoroughly recommended for reliability and all the VMPro extras that you currently don't think you need.
I have a couple of UCM systems and have no problems with them (though very aware that I appear to be the exception, so to be avoided unless you're very brave).
The main issue would be the cost of the extra licenses for the Preferred mode and for any extra channels. If you haven't already invested a lot into licenses, the new IP Office Subscription mode is well worth a look (if supported in whichever locale you're in).
Stuck in a never ending cycle of file copying.