I thought about getting it for my Better Bottles, but after looking on here I decided to go with Oxi-Clean. No regrets. Quickest clean-up and no worries about scratching the plastic. Look on their website. Great info about cleaning.
I bought one of the carboy cleaners; although there are threads on HBT about making one with some allthread and microfiber cloth I love hemorrhaging money at my LHBS. See bigscience's thread here if you're so inclined.
I don't own any better bottles and so far I've only had one carboy to clean with it. The carboy had krausen all the way up the neck and an overnight soak in oxyclean didn't get it off. I think it worked well, maybe not sufficiently better than a brush to justify the price but I'm happy with my purchase.
I have used one in a better bottle, glass carboy and keg and it works great. only need a small amount of water in the bottom instead of filling up all the way to the top. Well worth it for the 28 bucks I paid for it.
I totally regret not asking for one for my birthday, I was really considering getting one but then I said "PBW soak has never done me wrong". But then I just watched the awesome video on their website....