Well in terms of shell scanning, HMP has a limitation of 32 MB... MBAM has no such limitation. Both will perform full scans, but HMP doesn't have to be installed to do as such, it can while being portable. HMP includes I believe 5 different engines while MBAM is only 1. They will find different types of stuff though. Personally I would use both. If we're talking the free version of MBAM, neither run real-time. So why not use them both? I pretty much depend on a combination of VT Hash Check, MBAM Free, and Hitman Pro (portable). I have VTHC & MBAM in my shell. Since VTHC also has the 32 MB file size limitation, I use MBAM in the rare case a file is bigger than that. And do full scans with both Hitman Pro & MBAM about once a month, usually after patch Tue.