I just received my type F-II and C-II in the mail today.
First off, the F-II.
When I first turned it, it reminded me instantly of the ghost hand cube. Smooth, quiet (though abit louder and not as creamy) and also about the same weight. This new cube maybe slightly lighter than the previous type F.
I loosened the tension considerably and here is where this cube is just magical. It does not pop. At all. Ever. Incredibly fast, with good corner cutting and it refuses to pop no matter how careless you are. If anyone here had the type A third model you should be aware that that cube just does not pop at all due to the strange shape of its edge pieces (at least mine doesnt pop). This is basically what has been done to the F-II edge pieces as well though it looks a lot more solid and will no way in hell break (its triangular rather than two individual pieces sticking out ie. F-II has the hypotenuse)
So basically the F-II is a slightly louder ghosthand (even with the matte stickers) with the awesomeness of the original type F and the resistance to pop of a type A third model. Came very well lubricated.
Have not yet properly looked into my C-II yet but it seems to look like a type F and its indeed very heavy. Might update later.
C-II update.
I'm not sure whether the person that reviewed the C-II previously received a bad cube since his response was generally quite negative. My experience with it so far has been very positive.
Sturdy cube, with a very distinctive clacky sound. After loosening the tension quite a bit, it turns like a charm and it came very well lubricated like the F-II. This cube CAN pop but only if you are very careless but if you are doing solves on it, it shouldn't be a problem at all. Corner cutting is excellent and IMO will make an excellent speed cube for those people who like a heavier cube. It seems to be made of very good plastic and seems to have a premium feel to it - not sure why, but probably because its heavier.
I'd say that this is very similar to the old type F in terms of performance but with the solidness of an old type A (C-II is a bit lighter). Excellent cube.
I have no regrets purchasing both of these cubes as they all seem to be a step up from their predecessor and they combine the pros of different cubes into one.