I was looking for a DP 533 for quite a while and the market seemed to be $1200 bid, offered at $1500. I almost jumped on one, but instead bit the bullet and sprang for a DP 1GHz.
The 533 is a great machine though. First of the PowerMacs to use the 133 MHz bus, which was a major selling point for me. I was using a B&W upgraded to a G4 500 MHz via Sonnet's Encore processor. I was very happy with it but lusted for a dual processor machine. The DP 533 was my minimum requirement but seemed pricey compared to what else is out there. Had we seen new PowerMacs at MWNY last month I think the DP 533s would have come down to $1100 or so, but alas, nothing. Just made it easier to rationalize the dual gig I bought.