Actually I have been carefully contemplating your specific question. I now have the opportunity to purchase an SACD player. And...
I have been weighing the pros and cons of the much heralded and discontinued top-loading SCD-777ES vs. the front-loading, multi-channel SCD-XA777ES with an unknown sound signature and performance.
Even though I have no proof or have done any experiments regarding the stability of top-loaders vs. front-loaders, I'd probably have greater peace of mind with the top-loading unit. Less moving parts and less to vibrate or break.
I think I could be pretty satisfied with a good two-channel only system for music, and keep my less than hifi home theater system separate.
But who knows, that's the way I feel now. It would be nice to be able to use the same player for both a high-end two-channel system and a multi-channel one. :)