I just got my hands on some of these last Thursday.
They are nice figs but they are huge, way bigger than anything else I have.
I actually bought them because of this, as I got hold of some of the excellent bald heads from Max Mini, only to discover that they are too big for the figs I wanted to use them on. These heads are in fact too big for any of my figs except GW space marines or fantasy chaos warriors, (in my opinion of course,) which is a massive shame as they're wonderful little sculpts which I could have found multiple uses for.
Anyway I took some photos with a sample of the usual suspects to add to Denatus's size comparison pic.You'll see that the enforcer in the pics has a MaxMini head on it.

As to the castings, they're quite nicely detailed, but there are are a lot of mould lines to clean up, and they don't clean up as easily as styrene figs.
The figs are multi part, but the range of poses is very limited. There are two leg options in the pack I got, which while different, are very similar.
The worst thing about the figs is the way the appear to have been cut off the sprue, (there's no sprue in the pack, they come pre-cut off the sprue.) It would seem that the monkeys Mantic employs take very little care removing them from the sprue, hence the damage which Dwartist mentioned, and which I also found on my figs, as shown below.

I summary, they are nice figs, but:
1. They are huge, forget using them as humans with other lines, but they'd make quite good killer robots/aliens or gene modded super soldiers.
2. Clean up is a pain in the arse.
3. For multi part, they're quite limited in what you can do with them.
If it hadn't been for me wanting to use the MaxMini bits, I wouldn't have bothered with them.