Well, I've only used it once....but here goes!
I think it has pros and cons:
- much more convenient, you just put the bowl on your head and turn the dryer on. None of the sectioning that's required normally.
- much easier to dry hair 'right way up', which is better for me: you can read while doing it; and upside down tends to give me crazy curls!
- quick: it took 12 mins to dry the lot.
- my curls came out very very soft: not sure if this is coincidence!
- my curls seem a little looser/softer. This may be product related though!
- might not fit on your dryer!! lol
I'm in the UK, and got mine from ebay. It was about half the normal price. Maybe you could do similar?
I think, if diffusing is something you do quite a bit, with reasonably good results, then the sedusa might be good for you.