I prefer what they call "White Box" or a non proprietary system ( not Dell, or HP) My experience with proprietary systems has been less than desirable. I have come across all kinds of crazy issues from not allowing certain devices to work by crippling them in the bios, to odd ball screws that force you to buy new tools to work on the damn thing. Example: I guy I use to work with bought a Dell. He later bought a DVD player that wasn't on their list of devices. It didn't work. I put the same player in my machine ( one I built) and it worked. I had another incident with a Dell regarding memory. It worked in my old machine but would not work in the Dell. Both machine had the same memory specs.

My advice is to go with the white box any chance you get.