I've had both PX80U and 4280 and the Pio is miles ahead of the Panny. The PX80 is an entry level set and priced as such within the context of current year pricing. The Pio definitely has noticeably better black and much better processing, plus it doesn't suffer from low gamma (lost of image depth) like the PX80 (looks more washed out).
Back on topic - I'd go to the store and pull up the service menu to determine how many hours are on it, to use as negotiating leverage. The remote sequence is in the 8G Settings thread. With cosmetic blemishes, I'd probably get it down to $900-1200. Almost 3 months ago, my local BB was selling a perfectly fine floor model for $1350.