My first controller, a Dell running M3, lived outside, under the stand. I actually had two computers set up as controllers, one as a backup. I couldn't get the bios modified (I tried, hard) to power on from the panel- used the computer power switch, left it plugged into the wall. That worked fine. M3 went weird after several years of perfect runninng and wouldn't stay fixed, so I jumped to PP -which was just off beta- and bought the Tormach controller rather than deal with the 10 year old Dell. That works fine inside the stand (I don't use flood coolant anymore), powers on from the Tormach panel. I did stick a fan in the cut-out on the stand; mostly, don't use it- no need, and it's noisy despite vibration isolation.
Net, I've tried both, both work fine, and with two separate non-Tormach controllers (both Dells, one an optiplex) I couldn't find a way to mod the bios no matter what I tried. In that case, I just left the computer out where I could hit the power button.