When talking about Password Managers (and security in general), I think it's important to keep your threat model in mind.

Is LastPass going to protect you against sophisticated State, or even potentially Corporate attackers? Maybe not. Will it protect you against random hacks and insecure sites better than just reusing the same password that you can remember? Yes.

I generally agree though that this is an area where open source software is preferable. I'm also really intrigued by the work Keybase is doing and hope that it might spur some interesting solutions for web auth as well.