There are password managers like KeePass which store all the passwords in an encrypted container on the local machine. I would have to copy this container over to other machines to be able to have my passwords there as well.
Then there are password managers which are essentially like KeePass but store the password container online.
And then there are algorithmic password generators which, based on a master password, create the password for the currently visited website on the fly. Examples for such online password managers are SupergenPass and PWDHash. All I need to carry around with me is a tiny bookmarklet (which gets synced across browsers) and the master password in my head.
What are the advantages or drawbacks, security-wise, when using the online password managers of the 3rd category? Is there an online password manager which addresses these drawbacks while providing the advantages?