Aluminum cases being cooler than steel cases are a myth. That being said, it does feel alot nicer and you feel like you're getting the sort of quality you paid for.

But, steel cases have some advantages too:
1) Cheaper
2) Sturdier. Say what you want, but a steel chassis is less likely to vibrate/resonate/hum than an aluminum one. I hate the way my Lian Li panels can rattle, I had to remedy it with dampening material and velour strips.