I bought one (4/3 not m4/3) by mistake, it came with a Chinese adapter and was £200, I really like the lens but had to change the iffy adapter for a genuine MMF-3, I luckily I got it for a really bargain price, about £70, it was like new. The focus is slow, but that doesn't matter too much for the job it's used for. The full fat 9-18 4/3 isn't a very big lens anyway.
and.. I had CPL and big stopper filters at 77mm. the 72mm filter thread just needed a step up ring to make these usable.