The only thing I've used CS Live for is to check if my company's site works in all browsers because when I read that I could upload InDesign and Illustrator files for review but only to one workspace (or whatever it's called) I stopped reading and closed my browser. I don't want my clients' files mixed in one workspace, and I definitely don't want to pay for something I know 99% of my clients won't appreciate.
My clients don't want to sign up to a site that's not localized, being forced to learn to use a non-localized interface just to check files that I can also email them as PDF, letting them reply by email or phone.
Maybe I'm misinformed, but once I heard Adobe plans to charge $200 to $300 a year for CS Live I completely lost interest. It's partially my clients not being willing and/or able to work with a site that's in English, making the learning curve quite steep even if I came and taught them, but doesn't that defy the purpose of a service like CS Live?
Right now I'm kind of wishing I could uninstall the whole CS Live thing from all of CS5 as it takes extra time to start every appllication because of those (to me) useless features.