Depends what you're buying/selling...generally, the more expensive the item is, the bigger the risk you take dealing with ebay.
I would HIGHLY recommend going thru craigslist if at all possible...while you might not get as good a deal, at least you can deal face-to-face with the other party and deal with CASH.
As a long time ebay/paypal user I wouldn't recommend them, and would only use them as a last resort (ie buying/selling peculiar "junk" items; getting the most value out of games/systems instead of getting "raped" going the eb/gs trade-in route, etc.). Also, another thing to be aware of if you decide to do the ebay thing is that people will probably give you a hard time (both as a buyer and seller) with your new user/low feedback that will probably take you awhile to build up.
my 2cents.