The Yamaha Pocketrak CX is a version of the Sanyo Diply Talk ICR-PS1000M recorder. Somehow Sanyo manages to get 20+ hours of recording time from a single AA cell. This recorder can capture WAV files at 16/44.1 and 16/48, and can record MP3 up to 320 kbps. The recorder is unusual in that it uses microSDHC memory cards, the same type used in a cell phone.
The Pocketrak CX internal mics are no better or worse than the mics built into the portable recorders we talk about here. There's a 3.5mm mic input for your pair of external mics or a line in signal. The CX's preamp is OK, definitely not in the same class as everybody's favorite, Edirol R-09HR. The CX has a mic sensitivity switch, limiter, and high pass filter.
The CX I looked at had a poor quality headphone amp. My test recordings sounded a lot better when played back with a computer.
The Diply Talk ICR-PS1000M was introduced a little more than a year ago. Sanyo updates its model line regularly, so it's possible that a new model is coming soon.
Should you buy one? I would at the price you quoted, and use it as a music player and for casual recording.
Flintstone