I have not built a Sig kit but the GP kit was excellent from the clear and easy to understand plans (my 1st kit) to the quality of the wood. The kit gave me great confidence in building many more kits and I am currently 1/2 way through the TF P-51D which is an excellent kit that makes me look like I have been building for years. I like the variety of warbirds available from TF & GP. I have just finished converting my garage to a shop (walls lined with 3' Melamine lined benches). The woman and 2 children in the other part of my house say I have acquired and addiction. I guess I'll have to be nice to them so they will give me another TF kit for Christmas.