well i cnt say nething bad about my pioneer

 

Only thing you really have to be careful about on Ebay, is making sure they aren't refurbished, and you get factory warranty.

 

The only problem with eBay are bad sellers- check the feedback and the length of time they've been selling and purchase from the better dealers. I have made at least 2,000 transactions on eBay since 1999 and been burned 2-3 times.
Just bought the Alpine 9857 unit with iPod adapter, shipped, for $290- Crutchfield wants $350 for the HU and another $30 for the adapter, plus tax. Crutchfield is great (I have used them many times) but if you know how to install stereo equipment (even a little), eBay is far cheaper.
Good luck

 

Alpine pwns all in the ipod interface. eBay is good, just make sure the auction looks legit and the seller has some good feedback.