Zero consistency between the browser plugin, the vault, the app, and the mobile app. Even within the vault there's little consistency between different panes.
I'd like to believe that they know what they're doing crypto-wise, but damn that UX feels mickey-mousey. Even something as simple as using up/down over the autocomplete list misbehaves.... ;(
... and don't get me started on Basic Auth support on Chrome OSX
I only use it because I have to at work. 1Password is much more convenient.
However I think that is something that could easily be improved once the guys over at LastPass realize they must invest more in the UX. I for myself did already open a support ticket for that. If everybody would do this, this might raise the attention.
On the other side it's not so bad from a functional only perspective and the pricing is fair - I'll give it a chance and stay another few months with them.