I had the 45TX which was the predecessor of the 55TXI. It was a very clean, detailed sounding receiver and the MCACC EQ was effective in my room. In the short time I spent with it, it sounded just like my 45. I have had occasion to check out the 55 via i-link also, and although it wasn't a carefully controlled test, I didn't find alot of difference in overall sound quality between the i-link and the 5.1 channel analog in.
Flexibilty wise, however, it is the preferred way to go for bass management and time alignment.
I'm going to get the XR-70 and the DVDS97S for DVD-A via HDMI. Unfortunately, I've heard the DVD player isn't going to be out until Sept.(hopefully, that's wrong).
I stumbled upon this Forum after doing a search for the Panasonic receivers after reading about some positive comments on AVS. I've really enjoyed reading the threads here and it has piqued my interest about the digital amps. I might even try to find a closeout 25 or 45 to check it out before the 70 becomes available.
Anyways, having not heard the Panasonics, I can't comment directly on comparing the two, but I will say that the Pioneers will compete with anything in their price range. I actually preferred the Pioneer to the other offerings from Yamaha, Denon, and Sony at the time which is why I bought the 45TX. What intrigues me though is the quality some are reporting from such inexpensive components. Obviously, it will be much cheaper to get into the Panasonic set-up than the Pioneer. If it is as good or almost as good and you don't have alot of analog components, it'll be quite a coup.
I wouldn't expect there to be a difference from the digital connections themselves as they are both more than capable of delivering enough bandwidth for the applications they were designed for, but of course, overall quality will be affected by the upstream and downstream components.
I'm real curious about how the 70 and the 97 will perform for DVD-A. Although I don't really have a bass managment problem right now for hi-rez(I think it is has been a way overexaggerated problem for all but those with the smallest of satellites), I like the idea of getting the decoder out of the player and into the receiver.
Hopefully, we'll see soon.