My old faithful mixing drill has died on me. So its time for a new one. Now i know the Refina Mega Mixer has been discussed lots on here, and seems to be the brand to go with. But what size would people recommend?, MM21 or MM30? I'm a bathroom fitter, and do all my own plastering, but i'm not doing it everyday. Im only really knocking up skim, board addy and bonding. I occasionally take on some plastering jobs for friends in the trade when whey need a hand. Basically is the MM30 worth the extra Â£100 or will it be wasted on me?