I love the idea of Channelling Positive Energy, and I wish I could keep a well-run cleric alive in my campaign long enough to use it (I DM Kalamar btw). Clerics are my favorite class, and they are one of the easiest to get a plot progressing (let alone keep the party's a$$ out of the frying pan) and are naturals when it comes to role-playing.
I agree that the Kalamar PG needs errata on these abilities, mainly not because some of the abilities are useless (EVERYTHING has a use at some point) but mainly because of the disparity in DCs for saves (or saves at all?!?).
Keep a look out on ther Kenzer boards for errata!