I fly the S 1.40 version... knife edge isnt brilliant, you can fly through a knife edge loop and come out predictably but it takes lots of power... personally i think it's too long. Mine has been modified for better knife edge and the results are noticable, but its still not excellent.

The funtana pro is supposed to be a lot better but I think the C140 still wins in the KE department.. thats not to say it does everything better though.