The V16 Ebonite is a great piece. A T6 is what I started with, moved to a T8 for a while, and just went to a T9 couple of weeks ago and played a loud Blues gig on it last Saturday. It blew me away and I got a lot of compliments on my sound.
The T6 would be a good step from the Yamaha 4C. It does have a bit of resistance though, I would imagine somewhat similar to the 4C. A great piece that gives a lot for a comparably small cost. As mentioned already, they do have a fairly high beak, so it might take a little time to get use to. For me they are the most comfortable pieces I have played, but everyone's physiology is different.