I immediately gravitated toward the front end... no, I take that back, the first thing I gravitated towards was the seatcluster, but I figure I should start at the front for presentation purposes...
What can I say...you guys have probably been staring at the "stepdown" dimensioning of the headtube (and fork) as much as I have. Is it just a design feature? Does it actually make things structurally different? I'm not sure, I kind of don't think so. I'm just so glad it doesn't have any of those "zertz" like inserts as far as I can tell. I guess you either like it or you don't. I probably like the clean lines of say, my C59 or C60 a bit more, but the new design is in keeping with the rest of the frame’s tube shapes I suppose. Sort of carries the C60's lugs that matched the shape of the tubes to a new level I guess.
Then, there's the same design feature in the fork...
Again, does it really do anything performance wise... I don't know but I'm thinking I wouldn't be able to tell if it did. But it does distinguish the C64 from it's older C60 sibling, and that's part of what any new model needs to do. You're not going to confuse this with a C60, a very important aspect of marketing. This is the "latest and greatest", and it's easy to tell them apart. The fork does have a new profile and it's very nice.