I flew a friends LT-40 ARF and really enjoyed it. I learned on an Avistar and found it to more versatile. The Avistar could do most of the basic stunt pattern and did it with ease. The airfoil makes the difference which made it a good second plane as well.
However, there is nothing wrong with the LT 40. There are a lot of good trainers out there and SIG makes some of the best.