I've bought from both, and they are both top notch people. Brian is a small oepration, I've talked a lot personally with him on the phone, and on pirate. Marlin is always overworked, it can be hard to get through on the phone, but he's also known as one of the nicest guys in the industry(which seems that he's holding back his business, because his #1 priority is making good parts, not selling lots of them). Hehehe, Marlin sends XMas cards.
EIther is a good buy. You can buy Timken replacement wheel bearings for a good price at your local auto parts store. I just did mine, was about $15-$20 per side for the inner, outer, and cups.