My experieces have all been great (both as a buyer and seller). It's a terrific place to sell stuff with no limits to the item description or number of pictures one can post. Plus, there's NO commission (thank you, Leon!)
The only minor pet-peeves I have are as follows...
1. Certain people only interested in pushing for outrageous deals, far below market value.
2. People who inquire or state interest in an item, but do not have the courtesy/communication skills to send a follow-up email or PM. If you have a change of heart (or incur other expenses) please just communicate that, so the seller can determine how to proceed. It's not nice to leave people hanging...
Otherwise, it's all good here