That price for the RXDP20 is WELL below dealer cost, so I guess it did fall off a truck. The JVC units are fabulous values...sound great, well-equipped, BIG and BEEFY.
I have a THX Ultra-certified DP10, it's terrific, albeit it doesn't have all the latest surround modes (no skin off my back, actually). The DP20 has the couple of newer ones missing (like DTS 96/24), but the one glaring omission left over from the DP10 that they didn't fix is....lack of audio delay control.
For many people this is not an issue, but if you have an outboard video processor it can be one at times due to the delay introduced by the video processing.
Otherwise, go for it!