I read an indepth review right now on the Mark 2, aka Adam and Eve Wand, aka "Zauberstab 2" and the Mark 3, aka "Wicked Wand", aka "Zauberstab 3"
The only real differences are both of them being compatible with 220V power and - wow - being lead free. It looks like it wasn't the cable insulation that got it banned after all, it was all the lead in the electronic components and the lead based solder which prevented that it passed the electronic certification process. I had no idea. Lead. Imagine that. God, I hate the sex toy industry sometimes. Also, they're not supposed to interfere with radio now? Alright...
There are some very minor differences in looks between the original and the Mark 2. And the Mark 3 is black. The power is the same - 624 m/s² (not that this tells me anything), as is the volume - 6.5 Sone or 48 dB. And while the specs given by the manufacturer suggest that the hood and ... thingy over the switch, splash protection or whatever you call it, on the Mark 3 are both made of silicon, they have the smell and feel of rubber. As long as it's not Jelly I can live with that.
Attachments might not be compatible with the Mark 3 since it's head has a 3 mm larger diameter than the Mark 2.
The black one is more expensive, about 10 Euros. And the forum link on the test site has all kinds of differences mentioned that the review didn't.
The M3 is much lighter. 450g compared to the 600g of the M2.
This weight reduction comes from parts being made out of plastic that are made out of metal on the M2.
The sound level may be the same, but the frequency of the M3 is much lower, which makes it seem less loud.
The head on the M3 is harder.
It doesn't feel as solid and well made as the M2. For example, it switches to the higher vibration mode before the switch latches into that setting.
The M2 feels more powerful, but not by much.
I'm getting the feeling I should have gone with the M2. More power, more "solid", better build quality... cheaper. It may not be black, but who cares. Not too late yet I suppose.