The only real problem that I've had is trying to hound people for money that they owe me and them getting pissed off at me for leaving negative feedback when ALL of my auctions say "Positive feedback will be left promptly upon receipt of payment. Item will be relisted if payment is not received within 10 days (no exceptions), and negative feedback will be left. Nonpaying bidder alerts and Final Value Credits will be filed on all transactions not completed by the bidder."
If you have any questions just PM me.
Good Luck with eBay!