"The trick is to compute passwords rather than generate and store random passwords.
LessPass generates unique passwords for websites, email accounts, or anything else based on a master password and information you know."
"Next-gen", "Anywhere, anytime", "Manage directly from your browser". These are all super cliched, really cheap phrases that I really dislike. The front page is full of them. If you're marketing a luxury yacht trip to people with more money than sense, then sure you're probably going to get good results by writing like this. But the folk reading about this are going to be pretty technical and I'm sure everyone would appreciate to see something like "We provide a function that generates a memorable password from the site name and your master password" on the front page, above the fold.
In terms of entropy, you may as well come up with your own function. Security through obscurity is bad (no one knows the function you use to generate site specific passwords) but it's better than security through less obscurity (use a public function that a bunch of other people are using).
You can't get free entropy. If you care about your passwords not being broken when a database of hashes is dumped, you need to use a long, securely generated, random password. Sure, this is better than using the same password everywhere, but it's not really an alternative to something that uses proven cryptography to generate secure unique passwords. Passwords generated using this are only as good as your master password, with some obscurity thrown in.