That's true for the time being. MBAM is an excellent security software program that really specializes in Anti-Malware as I'm sure you know.
For a one time fee of around $25 from what I have experienced is an excellent buy.
For myself, I am waiting for the final release of Avast 5.1 just to illiminate any possible dual issues arising from "possible" beta conflicts...But as soon as I feel it right I'll make that one time purchase 'for sure'.
Do you think running two on-access scanners is important for security?
Yes, of course it is... i have SAS, MBAM and other stuff... Security it's never enough.
Although, i'm thinking about get the Pro Version of MBAM... maybe, as a present of Christmas for myself. :p