Dell has better customer service, and better systems, IMO. All things equal, I would take the dell.
However, there are other good systems out there as well. Have your friend check out
www.buyabs.com and
Systemax computers. I'd rather have the ABS, myself, but a friend of mine swears by Systemax. He had a problem with a CD burner in one of the systems he bought, and he said they changed it out no problem.
Systemax is more a 'value' type system than Gateway or Dell, and ABS has a lot of gaming systems that are cheaper than Dells. They have the basic entry packages as well as they high end systems. Last time I priced through them, they were quite a bit cheaper than Dell.