malwarebytes is meant as a complimentary antimalware option, not to be a standalone product even in the pro form. As to being able to detect rootkits, it has the ability to detect rootkits as well as you are able to detect a stealth plane before it drops a bomb on you. Their anti-rootkit is still in beta, and has been for at least a year. If it were in RTM it would have been incorporated into their pay for software.
I never use MWB as an AV product but as antimalware. It works extremely well in most cases. If I cant remove it with this then chances are format and reinstall is going to be least time consuming option.