The last dell I had was a core 2 quad, the first intel quad core early 2Ks?. It was a good deal from their business section, I think from memory it was like $750 and it came with a 20" flat screen. I stuck a 5850 in there and it served me for years, and then a few years after for my kids. But those were the old days, when Dell actually shipped decent stuff for a good price.
At work we have tons of Dell engineering CAD workstations and they are decent too. Xenons of different flavors over the years. Lately for the last 3-4 yrs weve been getting Lenovos and no difference really aside the better tech like M.2 drives, better faster ram, etc... Out of the 100s of systems from Dell, each costing $3500, I dont think aside some HD and video card failures here and there, weve had too much trouble with them. Same with the Lenovos. Next up work decided to go with HP, so I guess those will be put under test next.