I'm using Maxthon2 as my main browser, and the integration with RoboForm is flawless. I've seen that they've released now Maxthon 3 (an alpha version), and it's definitely looking much better than version 2, however since it's in alpha no features are enabled and thus no love for RoboForm. If they'd only add a toolbar support, I'd be all over it since I'm not that happy with version 2.
Anyway, if you're a Maxthon user it's worth downloading the version 3 alpha just to give it a short test drive (it installs separatelly).
Disclaimer: Some of my posts contain affiliate links (e.g. RoboForm).
