I actually started with their newer stuff and worked backwards to the beginning 
I read their Wiki entry last night as I wondered why they were away for so long. Those must have been some loud-ass concerts!
Quite loud: I knew someone who saw the MOB shows in Austin, TX (1980-82). Besides telling me that his ears rang for a week, he said the only gigs he heard louder were The Who in the early/mid 1970s.
To be fair, it doesn't take much grunt to overpower a cement-floored, basement bar...