I have used high end Dell's (Precisions) and not had any major problems with them. You get what you pay for. With MAC's you don't have to worry about that as they don't use cheap components.
I have been working on a PC all my life and I know how they work so I can provide my own tech support. Recently I have been working in a MAC office and I have to admit MAC's just work better than PC's. My PC laptop could not find the network printer because the IP address assigned to its print server was way out of our network range. The MAC's did not care, they just printed anyway. I changed the IP address and the MAC's kept working without a problem. In a PC you would have to go and change the settings in your computer before it would be able to print to the printer with a changed address. In the printer driver you have more options like you adjust the margins or get ride of them where in the PC you are stuck with the default.
I always thought it was the other way around. MAC's have less hardware variable which makes it much easier to design a stable usable interface.