Very good answer and comparison.
steve
Aaron-
Wet sprayed cellulose:
does have a higher R-value than fiberglass seals up the cavity better than fiberglass does not rquire a vapor barrier (per mfr suggestion)
it takes a long time to dry out studies have shown about a 20 to 30% improvement in "overall insulation" performance so it is better than fiberglass
DIY fiberglass is a lot cheaper than spray cellulose or foam. If I had an open attic & was in the market for insualtion I'd go with spray cellulose.
I forgot where you're located so do you really need super wall insulation?
Foamboard (DIY install) could get you up to R-18/21 but the stuff ain't cheap.
cheers Bob