I've install RH7.3 and some EDA software like ICFB in my PC, everything seems to be fine. The only problem bothered me is that each time after the system boot up, the system seem to run some kind of "self test" programme for a few minutes, and you can hear there are very heavy hard disk read/write. Everything become very slow, I never see such prolbem in other linux system.
Rh7.3 is not a good choice .Rh8.0 is not good too,it's too slow,but better than rh7.3.
Debian is my choice.it is faster , more flexible and more stable.