My only recent experience with Pioneer was one of their SACD players. It had issues playing some discs, and Pioneer didn't even have any firmwares to fix the issue.
So in terms of network and technology, I don't think Yamaha & Pioneer are any better than Denon.
But I think in terms of sound quality and performance, Denon, Pioneer Elite, and Yamaha are very even.
DenPureSound has the Denon 4311, and he doesn't seem to have any network issues with the Denon.