Has anyone tried out both the Onkyo TX SR705 and the TX SR805, most especially with the Sierras?

I am looking at both of these to replace my Panasonic SA-XR57. I am currently running Sierra 1 mains, CMT 340SE center and surrounds. I am hoping to get a Sierra center, maybe even this month if things work out.

I guess they both have the same upconversion with video, I really only would use that with satellite, LD, and the odd VHS tape I still use. I have a PS3 and an Oppo DV-980H and will probably use the upconversion of those players, so audio is the main concern I have in comparing the two recievers.

Both will do DSD over HDMI and have great reviews for sound and such. On the audio end, it seems to me that the only differences are the power supply which gives the 805 the higher THX cert, and the more powerful amps. So, the questions are, what difference in audio performance do these other differences make and did I miss any other audio differences that matter?

If I can go the cheaper route without regretting it too much, I will be able to get this done much sooner. That said, I am looking at my next reciever as a future preamp since I am hoping to eventually save up enough to get a separate, preferably class D digital amp some time in the next couple of years.

Any input would be greatly appreciated.

Thanks,

Chris