TouchID is supported for LastPass in Safari. It isn't (yet) supported in the LastPass app itself (though you have to enable TouchID there).
LastPass on iOS is very good indeed, within the limits Apple places. With iOS8 it's gotten better, but not exactly the same behavior as in a PC web browser. For example, the only place LastPass can fill in HTTP Basic Auth requests is in the LastPass app.
That said, I use it every day and it's fine. You do need Premium service to use LastPass on a mobile device.