I've bought stuff a few times from them but always with some hesitation, typically I use them just because they have a significantly better price on something.
Good experiences: bought my last set of wheels there (catalog item), and bought a couple of tow straps when they had 30' 30k straps for cheap.
The Bad:
They opened up a branch here in Columbus, OH several years ago and invited our club to have meetings there. The place only lasted maybe a year before it closed, no surprise to anybody in our club. We had previously had our meetings at a pizza place that had a nice seperate meeting room....and the 4WP place made us sit in the non-AC 100 degree garage with the air compressor running in the background. I tried ordering parts from them a few times, including a Lock-right which the sales guy tried selling me a Traclock because "it's the same thing" even after I took in the catalog page from the Lock-right webpage. Also ordered an extended brake line, got me the wrong part and then tried to charge me shipping even though I went to pick it up at the store. I looked at some "custom" work they were doing and it was hillbilly deluxe scary! Their lead mechanic built a CJ-7 that looked pretty impressive from the street (it was always parked out front) with lime green paint, full-widths, and 42's. After looking at it closely it was pretty shoddy. Rusted out frame, hacked off factory spring and shock mounts (I swear he used an axe)...didn't even try to clean it up, just spray painted over it. Front axle was a D44, with stock gearing, stock 258, etc, etc.. He sold it to some poor fool and that guy brought it to one our club's open rides...that POS puked all over itself 100 yards into the trail on a hill that Jeeps on 33's could make with no problems. Took us an hour to fix it good enough to get it back to pavement.