Rebel, here's my suggestion:
1 - buy 1 player. don't spend too much on it unless you have a lot of disposable income. The Pioneer 578 s-a plays dvd video, dvd audio, sacd, and all the other fun stuff.
2 - get cables to plug the 6 channel out from the DVD player to the receiver.
3 - get a fiber optic to plug from the dvd player to the receiver.
4 - listen and see which sounds better to you. DVDA and SACD will only play through the 6 cables, not the fiber optic.
For DTS, DD5.1 and Stereo, so long as your receiver can decode them (if it's recent from a few years ago, it will decode them) you can try playing it through the fiber optic or through the 6 channel out.
a player that can play DVDA or SACD will not sound any better than one that can't, however, you can get one that does for the same price as one that doesn't, so might as well buy it. Many SACDs have SACD stereo mixes on them.
