You have to watch out a bit with the s-types, they are harder to ride then the rrd's who are more freeride. I can sugggest a carve boar with a simular volume. Carves are easier to ride, have a wider sail range and have a bigger range of public then the s-type...
don'"t worry too much about side cuts, they are just like carves in the boards that reduce friction, but if you want to see them clearly check the F2-website (along with mistral still leading in windsurf, don't reject the elder brands).
I must admitt that in my experience these new boards are more frigile. especially due to heat changes... thats when starboard is the best choice with it's centre screw to relieve pressure that builds up because of this heat. Baords come out of cool water into warm sun, that can end in disaster. I had a mistral n-trance which was completely distroyed because of it, the endtire bottom got torn open by one little scratch after we had driven through italy that year and pressure built up, we put the board in cool Dutch water, good windsurf but it was the end of that board.
Another this is scratches. These are lighter boards but they scrach quite easily compared to older boards (i may be young but vintage is my side hobby
) . soft handeling is important if you want to keep ypur board in shape and i also suggest you buy Dram which is more durable then Wood.
Also, if you put these on the roof of your car you have to put them on with the top down alse you can dent the bottom, which oin it's own isn't really a problem and doesn't infect sailing too much but may lead of other problems.
Further more, check out what there is on the marked. When i started surfing again 3 years ago i had the same and ended up with mistral again, but i bought a beginner progressive board which wasn't my best choice though i learned a lot very fast. A year after i bought my starboard Go139 which also i progressive but which you can use much longer because of it's smaller volume and because of it's sailrange (if i buy a smaller freeride, i'll use the Go for speed purpouses, it's a beauty!!)
Any more specifics? feel free to ask away, thats why there's this forum!!
Have a blast and good luck!