Well my new MARS 3 light turned up today. It's different, as Saundie pointed out.
I've got to say I'm a bit meh about it. The light output is quite significantly higher but the plastic is noticeably thinner and more fragile, the toughness being one of the reasons I bought the old model. The clip on the back feels quite brittle and I'm not convinced there was any need to change the latch mechanism, which also feels weaker. People have complained about the fact that the screws used to corrode, but I prefer a light that screws closed. Could they not just have used stainless screws?
I'll put up with it, but I think it's going to break if I drop it.