I have the Yamaha RX-V1400. By far my biggest complaint is the "multi-channel" input is a toggle selection, not discrete. This means it is impossible to automate switching to SACD/DVD-A via a remote control macro.
I also don't like the menu design and navigation -- it's very complicated. You eventually get use to it. The manual is poorly written.
The YPAO auto-EQ mostly works, but I've seen it do some odd things that are probably errors.
I think newer auto-EQ systems like the new HK system are probably better.
Other than those things the Yamaha sounds fine, and it's a good deal for the money.
