I've never used MM, but I know a couple of locals who have had great success with it. Price is he main deterant for me. Certainly nothing wrong with a plain old
DSB, I have them in both of my tanks, and they work, but I think I'd be willing to try MM if it weren't so expensive. I don't know how much nutrients and
trace elements it might release, or if it's anything you wouldn't get from regular waterchanges, but it stands to reason that if the elements are in there, and are soluble, they would indeed be released via osmosis.
IMO cheato is what you want in a
fuge. Calerpa grows faster, but it has so many drawbacks. I'm STILL trying to get it out of my
fuge a year after switching to cheato.