Mark at Davis Square Martial Arts is great; I studied there for five or six years before deciding my body just couldn't keep up, at least for now. But I intend to go back for Tai Chi eventually and would probably go back to Mark when I do if I'm still in the area. I can assure you, you will not deal with chastisement there. I have heard good things from a couple of friends who studied at the Tae Kwan Do place in porter square; but I wasn't thrilled when I walked in there. I have heard nothing but good things about the Aikido dojo in porter and was impressed by the class I watched there.