I have a 4*40 kit but haven't begun building it yet.

I would vote for the Sig Kavalier or Sig Somethin Extra. The Kavalier is a shoulder wing trike with very good habits. It tracks straight and does just about all of the pattern maneuvers. It has no bad habits. The Kav was my first kit and 3rd plane and I still love flying it. It is just a quality design. I'm not sure about knife edge with it. I just thought about it and I don't think I've tried it on the Kav.

I mentioned the SE because it is an excellent second plane if you keep the rates very low. It is docile, fun, and a great plane to land. It also will fly a lot of the pattern stuff, but maybe not as well as the Kavalier. Some may argue this. You can turn up the rates on the SE as you grow into it. The SE is a very underated kit, and very flexible one as well.