I'm using the Ayre C-5xe. It is an excellent and reliable player (though it is a universal format player instead of just a CD player). I think any players in similar price ranges aren't goint to be substantially different sounding as some people are suggesting, as long as they are designed to protect the delicate electronics from EMFs and use quality DACs, OpAmps, Clocks, etc. I think either player will be a great choice, but I would personally go with Ayre because I've spent time dealing with the employees there because I have bought more than one piece of Ayre equipment for my setup (C-5xe U2 player, K-1xe Preamp and MX-R monoblocks). They're available to answer questions, are extremely helpful and care deeply about customer satisfaction and their product quality. They helped me numerous times with questions I had about their equipment and how best to set them up, recently with questions of how to apply the unity gain so i can use my surround system and my Ayre K-1xe preamp together.
I would call Ayre as someone else suggested and ask what improvements were made to the "e" version. That is the easiest way to be certain you are getting the truth, and you will get to see how nice they are to deal with...
Since they are in the same price range, you should check out the Meridians also (G08 or G06) if you can. I ended up choosing the C-5xe over the G08 because it played all formats in stereo and the rest of my gear was going to be Ayre, so I would benefit from using the same gear in balanced mode all the way through to my speakers. Both Ayre and Meridian are excellent players IMO. Unfortunately I've never tried out the audio Resolution Opus, but i have heard great things about it also.