Dentrobate, the poor performance issues would be caused by the options that your school chose. They probably went with a pretty low-end model for their lab. You'd get used to the different operating system pretty quickly if you used it regularly.
That being said, I'm thinking of getting a new laptop sometime soon. I'm willing to spend a fair bit, and performance and durability are two big priorities. I've been a lifelong PC user, but I'm seriously considering switching to Mac because of some good recent experiences and horror stories about Vista. I figure that I'll have to get used to a new OS with Vista anyway, so I may as well just go with Mac OS rather than a poor imitation. On the other hand, I'm wary of some of the compatibility issues with Macs and I like knowing exactly how everything works on a DOS/Windows based machine. Any of the computer experts around here have any thoughts? I've had Dells until recently, but I don't think I want to go with them because of a long string of problems (4 power cables in one year!)