You can't go wrong with either plane. The Slow Stick is definitely more robust and handles a decent amount of wind, but many people have learned on the original GWS Tiger Moth.

Don't confuse the original Tiger Moth with the new Tiger Moth 400. Two completely different planes.

My advice is to be wary of "ready to fly" airplanes. There are some that are okay, but many are just there to steal your money. That el-cheapo Beech Staggerwing might be okay in the hands of an expert, but I would bet dollars to donuts that it's not very stable. A very successful RTF design has a high-monuted wing, a pusher prop, and a V tail. An example is the Firebird Commander.