I actually own both players - the Ayre C5Xe and the Cary 306 SACD. I've had both of the players for over a month now. They are both unbelievably good!
Thus far the major difference appears to be that the Cary is more dynamic and possesses more "slam", while the Ayre is slightly more laid back and has (slightly) more inner detail. I actually prefer the Ayre for acoustic music, male and female vocalists, and chamber music, while the Cary really shines on massed instrumental, symphonies, sound tracks and music of that ilk.
Oh, how I wish I could keep both - but - ultimately I must make a decision between the two. I really love both of these incredible players - on SACD and on Redbook - both are wonderful - they just sound different.
Which is right? Which is the "best"? At this point, I'm really not sure. I have both units connected to my preamp and every time I switch between the two, I am convinced that "this one sounds better".
Since "decision time" is rapidly approaching, I guess I'll have more to report later. . . . . So . . . . . Later . . . . . .