Seems like everyone build this scheme. Seriously, there are many browser plugins and websites implementing it, and almost all of them ignore research (I'm guilty too). Also, most of them use fast hash functions instead of proper password hashes.

Here's a quick analysis of pros and cons of password generators compared to password managers: http://crypto.stackexchange.com/a/5691/291

I used a password generator (my own) for a few years, and I'm happy to use a password manager now, which is safer and makes me avoid keeping certain information in my mind (e.g. if I already have an account on this website and what's my username for it).