Budget should be on the top priority list. I've read and seen some problems w/ MS, but you cant beat the price.
I think no matter what support should also be a top choice. On this site, MS is very well supported, but I think the learning curve is also much higher.
From reading, the Wolf system also seems to be up there w/ support and features on this site. At least one admin support it's which is a plus.
I have an uninstalled Tec3. Don't have it installed yet, but I know it is one of the top of the line units. I got a very good deal on it so I almost had to get it. I"m still in the collecting parts phase of my build.