In my experience in the workplace, and at home (gaming), I have found the Dell to be rather limited in it's upward mobility.
We use very advanced software (i.e. very large .exe and add-ons, etc.) at work and sometimes are locked up despite megs of ram.
Our IT consultant has oodles of reasons for this but I neither understand them all, nor is there enough room here to enter them.
for being vague w/the initial post.
A higher end Dell is a decent pc for most tasks, but not heavy duty.