I personally prefer to buy on eBay off of someone from the board or TapeOp, or other boards. I like knowing the history of a person, and I like the added feedback of eBay. I've been ripped off on this board, and have bought broken gear on eBay, and have bought gear on this board that is in way worse condition than stated, so to have both sources of info seems the best way to me. I'm willing to pay a little extra for that peace of mind.
The way I see it, the more info I have available to me, and the more comfortable I am buying from someone, the better. If I have to pay a little more to have a little more comfort, then it is worth it to me. Likewise, you can't expect me to pay a premium for my used gear and then sell it for peanuts to be a nice guy. Everyone I buy from is trying to get the most out of their gear, as they should. I don't fault people for that. I don't go to the car store and offer to pay sticker price for a car. On the flip side, I don't want to sell my gear for less than it's worth, when I paid full value for it on eBay or from a dealer. I just don't think it's fair to expect me to give a huge discount to someone who I probably don't know anyway.
If someone doesn't want to pay the premium that eBay gets for gear, then they should just avoid eBay, and hope that the gear they're looking for will show up on these message boards someday. If you want your gear now, with feedback and other things to go off of to help ensure you don't get ripped, then pay a little more and buy on eBay. I don'y see a problem either way. Live and let live I say.