I have a nitrotech n12 and i am really unimpressed. Someone mentioned Cartoni is rubbish, but i have to disagree and say they are 2 steps above manfrotto n12. On my nitrotech the plate release button broke off on the 2nd day. It is made of plastic. I was lucky to repair it. Then the head developed a hard spot in tilting action at the level position. There is resistance at the level position, tilting it further the resistance is smaller and gradually increasing as tilt progresses and counterbalance kicks in. So when you approach the level, the head always jumps. It is noticable at the 4kg setting and disappears at the 12 kg setting. Strange. I just wish, people would be a little more honest about the equipment they have. The n12 is getting recommendations a lot, but i think it is not deserved. I know that everyone is proud of what they have and buy, but still i wouldn’t recommend manfrotto nitrotech. Flimsy and unconvincing, awkward head. The problem is, there is not much else available. Everything is sold out right now or prices just too high.
I admit RUBBISH is a bit exaggerate, but to some degree, especially according to my criterion, a head which cannot hold throughout ±90° is rubbish. Please note this is a criterion much higher than the film industry, majority of camera men will not find Cartoni's counterbalance unacceptable.
I have used Cartoni 8, HD, 18, 22, of which I'm still using 8 and 22. HD is acceptable to me, but 18 is not. However these Cartoni heads do have a lot sample variances on the tilt motion, lots of my friends are not satisfied with 8 and 22 either.
Like Jochen said, Cartoni is somewhere in between these days. Some of their cheaper heads are aimed at the consumer markets like DSLR, DC, etc, but their Master series and above are clearly professional kits. Speaking of Manfrotto, their products are almost all consumer, but I do find the Manfrotto N series a good company to some light weighted binoscopes and I believe people are honest with their opinions. There is no reason to be dishonest on this point, you may got a lemen or something.