G'day Mate,
Just one more point that has not been mentioned here, so far, is the fact that when I changed my girlfriend/ students plane from PPM to PCM I noticed an increase in range with the aerial down, because as usual after changing receivers in her plane I did a range check, it went from about 30 paces, before any jittering, to at least 70 on PCM, JR 770S receiver, & I still had not gone to failsafe, meaning I still had good signal.
Also here in Aus there is only $19.00 difference between PPM & PCM, $119.00 for PPM & $129.00 for PCM, in JR brand anyway. And I think the advantages far outweigh the disadvantages, when you cnsider the price difference.