Well, note that the Marantz is limited to 2 channels of output and is twice the price of the Sony. OTOH, it has a clock input which the Sony lacks.
I have owned both albeit not at the same time having sold the Marantz, went to a redbook dac off a transport and then bought the Sony (I had just too many SACD discs lying around not getting any airtime) so I am only going by auditory memory which for me is quite short...
With the caveat that my Sony hasn't had too many hours on it and may suffer from lack of break-in (if you are a believer in such things) I found the Sony to be more detailed - it appears to me at least I am hearing details that seem new to me. The Marantz seemed to be more forgiving on poorer recordings (redbook especially) - is that because there are less details - I don't know...
Like some if not most equipment each has it's own "house sound" and I found the Marantz to be "smoother" than the Sony. The Marantz is a more robust construction with many items, including the transport I believe, taken from it's bigger brother the SA-7.
They both have a devout following and of course differ greatly in price.
I don't listen as critically as I used to primarily due to the fact that I just don't have the time these days so I could summarize that I could be happy with either player but I do think the rest of your system should help dictate which player is the best fit for you. If you have a very revealing system then maybe the Marantz is the better choice, if your system needs a "kick" then the Sony might be better suited to help get you there.
The best advice as always is to try before you buy but the Sony may be hard to come by to demo Vs the Marantz.
I am sure you will get differing opinions from mine but hey that's what its all about - we all don't take the same path to get to our destination.
i owned the marantz 11s2 and did not consider it smooth. i lent it to my friend whose system is different from mine and he thought that the marantz was edgy.
i understand that people have different systems, different ears, and different preferences, but i have never heard a marantz piece of equipment sounding smooth.
if the sony allegedly is more resolving, i suspect that it would not be to my taste.