Overall very useful . HOWEVER, latest Lastpass extension with Firefox 57 release has teething problems. They will fix these eventually, but I had to revert to FF 56.0.2 and Lastpass 4.1.67 (on Windows).

Problems:
(1) Would not Autofill several websites (eg, login.fidelity.com)
(2) Could not edit any site info through the extension
(3) Copy Password is temporarily missing, so very inconvenient to work around first problem