I give the Sig 4 * 60 a BIG thumbs up! I built mine from a kit over the winter. Flew it for the first time yesterday. Minimal trim adjust was needed on it's very first flight. This plane is joy to fly. I built kit to manufacture spec with a Thunder Tiger FS-91 engine. I did NOT have to mess with CG or anything. I just built it according to the directions and flew it. The only problem I had was due to a new TT engine that runs a bit rough and needs a little break-in time. Here's a pix of my 4 * 60.