I made the mistake of buying a Sig Somethin Extra as my second plane. I was not ready for it. It took me a while to get a feel for it.
I would suggest the Sig Four Star. The the instruction are straight forward and the parts that make up the fuse interlock so you end up with a very straight and true build. The plane flys awesome. For me it would have been the perfect second plane. Very stable no odd tendancies. Best luck to you with your new addiction.