Yes, Nick, I own the Pioneer 45TX, the previous model replaced by the 53TX and 55TXi. I tell you that its MCACC auto-calibration/EQ feature does wonders to your setup. Initially, I tried to manually tweak the parameters set by the receiver (yes, the system is so flexible that it allows manual alterations on top of the automatic adjustments on all level/delay/EQ parameters). But soon I decided that I could not beat the automatic setting.
The MCACC (and Yamaha's YPAO) audibly improves the sound quality of your system -- especially in the department of multi-channel imaging/soundstaging, as well as timbre matching among the main channels. You need to try it in your own room in order to really appreciate these benefits.
