I really don't see a problem with either the GP Ultrasport or the Sig SE as a second plane if the pilot has mastered thier trainer and they have an experienced pilot spotting for them the first several flights. If one really can fly their trainer well, they will be bored quickly with a traditional second plane. I actually had a GP-Ultrasport as my second plane and have no regrets, in fact I firmly believe it was the right decision for me.

I know many that have successfully used Sig SE's and Lanier Stingers as second planes. With proper instruction, many pilots are capable of moving from a trainer to solo flying these planes. The nice thing about these planes is that they are more honest in flight than a traditional second plane and they present a better platform for learning advance flight.