Agreed - focus on APA match rate and don't be fooled by inclusion of APPIC/CAPIC match rates. These can be substantially different and I'd recommend a school with a 75% match rate (all APA) over one with a 90% match rate (30% APA) without reservation. I agree that the higher the better, but as others have indicated it can get somewhat more complicated when you factor in things like mentor, type of program (e.g. clinical-science vs. scientist-practitioner) and a million other things that can impact it.
Since we are generally dealing with small sample sizes, I wouldn't worry about relatively small differences (e.g. a 5% difference in match rate in programs with 5 students entering the match per year is probably not a meaningful difference). Similarly, it will fluctuate from year to year so look at aggregate numbers. One year with a 75% match rate shouldn't scare you off from a program if it is consistently 90-100% in other years. Again, with small programs this could be a case of 4 people applying, 1 heavily geographically restricted person not matching and not much of an indicator of the program itself. On the other hand, if 75% or lower is occurring consistently (or it is trending downward over time) that is quite worrisome and I'd think very carefully about it.