I've had mixed experiences, but still purchase smaller items occasionally from there.
The worst problems I've had are a mobile handset that never arrived, and the cops never informed me how the case was progressing. Lost quite a bit on that one.
Bought an electric knife sharpener (not new) and soon decided it was past it's best days, should never have been sold. Tend to buy new only now.
CDs/DVDs that were corrupt and the buyer tried to avoid a refund by pointing out his ad said he was not responsible if the buyer's player was incapable of playing the format (no player can play corrupt disks). Had to threaten him with the small claims court.
Corrupt/useless thumb drive sent from abroad, and he never refunded the payment despite sending it back as requested. (Beware of sellers who use the word "honourable in their sellername, ask yourself why they need to say so.)
Substitute stuff sent without being asked, and getting no refund for the cost of sending it back.
Various other annoyances too.
But overall I think I've probably gained as least as much as I've lost. Buy new, but cheaper stuff, are good safety strategies. Most sellers are honest, even if buying used and dearer, but you run the risk.
Oh and don't expect either eBay nor PayPal to be interested in protecting your interests. In my experience you get the run around and excuses why you were not as covered as you were told, after all. They're just not interested in anything other than making money.