Tried the Schuberth C2 and found the following:-
Vents worked well for me, the pop down visor is great when the sun comes out and the lid is very quiet. Also vision is excellent On the down side I find it heavy, the side button to lift the front is awkward being off to one side and difficult to flip one handed and I found the internal padding a bit lacking. The other issue I had was trying to fit auto speakers and mouthpiece as the lack of padding means you have to rip into the lid to fit stuff. The last bit of bad news was misting from the visor, there is some sort of coating on the inside of the visor that does well when new but I got the inside wet and the coating peeled off.
The Multitec.
A lot lighter feeling, takes a pinlock, central release makes flipping front far easier, the helmet fits me better. It is also very easy to install an autocom if you need to as the lid has cutouts in place for speakers
It does not have the sound insulation qualities of the C2 but the extra wind skirt things that come with it help.
SO to sum up although the C2 has some good design ideas, particularly the flip down visor I personally prefer the Multitech