RE: carve or s type?
The Carve 101 is the logical development of the venerable Carve 99, (the the board for all reasons and seasons).
So it's very versatile, almost gybes by itself, and has a really incredible range of use.
But then you know most of this already.
The S-Type 104, is a little faster, has a slightly narrower range of use (overall, but mostly on the lite wind end of the spectrum), and is a bit more technical to sail and gybe, but if you've adapted so easily to the Carve 101, the S-Type 104 might be not be difficult for you at all.
Best bet is to find a demo and try one out, but I don't think you can go wrong either way.
Hope this helps,