I love Sig kits. I'm building thier old Bonanza kit. The box says its a "craftsman" kit. Boy, that word will make you stop and wonder what you are getting into. But it turns out, it is a dream of a kit.
I guess I had their Colt and Kadet Jr. I have a Komander in the box. I've seen just about all of thier kits and flown a bunch of them.
Sig kits go together just a little bit differently than other kits. Generally the builder cuts a few more peices for himself with a Sig kit. You aren't trying to fit a box full of die cut pieces together like most kits. You are cutting pieces of stock yourself and gluing them together and then sanding them smooth. Chances are that no two Sig models will be identical. But both will be nearly perfect. The customized parts you cut give the model that old world fit and finish that was the norm in modelling years ago. They aren't harder to build. They just fit together better.