I'm currently looking for a DVD-A/SACD and the Pioneer 578 seems like an obvious choice, for the price, as I can't pay much.
Is it a bad choice? Only thing I truly dislike about it is the silver color... but I can get along with that. What matters is, how is its SACD and DVD-A performance?
If your main concern is 2-channel SACD/DVD-A, you should maybe look for the predecessor: DV-563A (US) or DV-565A (EU). It had superior DACs, there was a long discussion on these player earlier in this forum.