I've had the KD-HDR1 for about two years and I'm generally pleased with its FM performance. Even if you listen exclusively to analog FM, you'll find the selectivity is very good and the audio quality is more "natural" than some of the competitive car radios with a digital IF (for example, the Blaupunkt Alaska). My only disappointment is that it does not decode RDS.
FM digital performance depends greatly on the station's signal quality. Some stations decode well, others at similar distances and powers do not, but this may be due to problems at the transmitting end.
However, the AM section suffers from front-end overload to a greater extent than most "classic" factory-installed car radios. If you drive past a moderately noisy power line, the wideband garbage seems to saturate the RF stages, causing a loss of digital decoding. But out in the wide-open spaces, along an Interstate with no nearby power lines, it does OK.
I don't use the CD/MP3 player frequently, but when I've tried that feature, it has performed well.
Overall, it's a good receiver for the money, but I'm not sure how the Wal-Mart version differs.