I haven't heard that one in particular, but 2 years ago I tested the CT700 and CT710 side by side. The main difference is the first has a normal analog amp and the second has Panasonic's new D.sound digital amp. I've listened to another D.sound player from Panasonic (forgot the name) more recently, but was reminded of the same sound signature as the CT710. Really grainy and blurred, like the music is traveling through mud, but at the same time thin and claustraphobic. It was truely the worst CD player I've ever heard. It made my old $30 GPX from Sears sound like sexy angel voices.
So unless their D.sound has greatly improved (as the Sony digital amps have), I'd recommend to avoid it. I've found that the Panasonic CT579v sounds very good - it's the only one still in production without D.sound. Slightly laid back, very natural sounding, and smooth throughout the frequency range - not like the distinctly seperated high/mid/low of the Sony DNE320 (which seems like a typical characteristic for cheaper Sonys). Its only fault to my ears would be a slightly rolled-off treble.
Another good option IMO would be an iRiver. My iMP50 is fairly bright and punchy and seems to stay coherent during complex passages better than the Panasonic, but at the expense of a less natural sound. The bass seems to lack something - it's a combination of getting a little sloppy and being slightly rolled off - not quite sure yet, but I'm still trying to figure out how to adjust the EQ. The worst thing about the iRiver is the build quality. I just got mine, but the motor already sounds like my grandpa with bronchitis. Also it's big and clunky and has an incredibly stupid reverse loading system. But hey, it's $20!
I'd recommend you look at either the iRiver SlimX models if you can find one, or a higher end Sony (don't know too much about those). But since the CT579v is only $50 at Sears and they'll let you return it opened, you might want to give it a try too.