I use these servers in my lab to run LMS, and they work fine (for small networks). However, you will not be able to run Unity on the same system. I simply reimage the servers with Windows 2003.
That said, the last 7825s I setup were a bit of a pain. The RAID drivers weren't included with Windows 2003 SP1 R2. If you can get one of these servers with Windows 2003 pre-loaded, and ready to go for LMS, you might be much better off.