I'm with valuehost (well, payhosting actually, but they're just a reseller I think) and I'm both impressed and annoyed at their service.
pros:
*full-on /php/mysql support
*you can ssh into your domain and nose around, and iirc they'll even let you compile some libraries or executables.
*most people have reported fast speeds from them. 700k/sec was the best I think.
*unlimited transfer - can't be bad
cons:
*phpMyAdmin hasn't been updated in a year or so
*a handful of people for some reason, can't resolve my domain name
*mail servers used to die, but that hasn't happened to me in over 12 months
A wise man once said: "I know that I need codes but I dont know the codes"