Actually I disagree slightly with thunder 18. I have the 54 and it sounded good without the MCACC. I definitely prefer the MCACC for the full surround. There are sometimes when I still prefer the direct mode sometimes for 2 channel listening.
The staff here love the Yammies, and they have the measurements to back it up. I was looking at the 2500 when I bought my 54. there were acoupole of things that pushed me to the Elite. The beefiness of the Mosfet amp, the larger capacitors, the ability to bi-amp, the simplicity of the remote. To me the Elite cast a deeper, wider soundstage than the Yammie -- I repeat, TO ME. I also like the Elite look better.
On the positive side for the Yamaha, I felt it was more neutral in sound, while the Pioneer was a little warmer. I like the concept of the YPAO using a parametric EQ instead of the fixed bands of the Pioneer. At the time of my purchase I felt strongly that I would be happy with either. I still feel that way.