I've got one of the Nikao cases myself (the MT-1000). I built a little Duron machine with it and the machine runs perfectly with Mandrake Linux 8.1. Granted, I can't check temps or anything, as my board (MSI 6340M) doesn't support that function, but I've had no problems at all with the machine. I had Win98 and W2k on it for a while as well.
Just my .02
Matt