I suggest you use the powerful search
function of this forum with "MCACC" or "YPAO" as query. You will get numerous posts such as the ones in this recent thread
. While a person (mwc) describes a negative experience with the MCACC in the thread, I myself, like quite a few others here, am extremely happy with my Pioneer 45TX's MCACC feature. So, back to your questions:
(1) Only you can really answer this one. However, I have to add that in order to fully appreciate the benefits of MCACC/YPAO, you do need to listen to it in your own room, although you can certainly experiment in a well-isolated dealer showroom, if the dealer is fully willing to let you play around with his equipment.
(2) The YPAO still being a few weeks old on the market, the jury is still out on this one. However, at least on the specs, YPAO's 7-band "parametric" room EQ is more advanced than MCACC's 5- or 9-band fixed EQ. Third-party measurements on Yamaha's amp sections are still forthcoming, too; Pioneer's amp section has been shown to be VERY robust by independent measurements.
(3) Yes, there are several standalone automatic room EQ/real-time analyzers available, especially from the "pro" market with quite affordable prices, such as the Behringer DEQ2496
. However, you have to know what you are doing in order to incorporate these pro gears in your home system, with regard to details such as signal-level matching etc. Also, these are 2-channels only products.