Boxx vs Maingear vs HP vs Rain vs Adk vs Puget

I'm looking at quite possibly switching to a windows based workstation after some mac hardware news comes out in the next few months. My primary uses are going to be motion graphics/compositing/3d and some editing work.

I've been looking at machines from: Boxx, Maingear, Puget, Rain, HP, Adk, Biway, and some others.

I'm not really that handy electrically. I'm not terrified of building my own machine but I'd really rather not be bothered with it, I've got other things to work on right now besides learning the ins and outs of building my own machine. What I'm wondering is, out of all these workstation companies that are out there, which ones are really worth it and charge a reasonable rate for their services without taking you to the cleaners? I've liked the systems I've seen at Maingear and Boxx so far as they allow me to customize a good deal and seem to stand behind their products but I've heard some people say they're overpriced. Some of the other configurers (such as HP) force me to purchase a certain graphics cards and memory configurations which I'd rather have more control over.

I guess I'm just looking for any advice or suggestions regarding dealing with these workstation builders, or any experience or opinions on any of them specifically. Any advice or information is much appreciated!

db

ps: My budget is between $4-$5k, but preferably staying in the low-mid 4 range.