Personally I prefer Onkyo 503/504 to Panasonic XR55, I just cannot like the brightness of the XR55. I like warm sound. Onkyo is not warm, at least close to neutral. To me, XR55 has all the advantages, no/low distortion, low heat, power efficiency, very clean sound, very good mids and highs. It sounds a little too bright to me, if you can accept that, then go for it. BTW, I posted the sale here and in Newjersey board at $169.98, it seemed nobody liked my Panasonic XR55. Now it is already on its w