I know what you mean about the excitement. I went on a buying spree when I first started out. I had trainers, 4*'s, a Sukhoi, a Cub, a Rapture, a Somthin Extra, Little Extra, 1/2a P-51, Profile Hots and various other planes.

The Sukhoi was too much of a handful for me. Miraculously, I didn't crash it though. Not bad anyhow. I ended up selling it after a few flights. I could fly the wings off the Somthin Extra and Little Extra but couldn't land either worth a crap twice in a row. Same goes for the 1/2a P-51. The 4*'s and Rapture were what I really needed to stick with but I convinced myself I was bored and moved on too soon.

I figured out my mistakes a couple years ago, took a few steps back and my flying immediately got way, way better, especially the landings.

I've also owned a U-Can-Do. It is very light, with a thick airfoil & huge wing area. That makes it float like a blimp. It can be extremely responsive though. The huge ailerons fluttered very easily which can shake the plane apart. I've seen horizontal stabilizers break off of them too. Like RCKen pointed out, they are fragile. That's trade-off of the light weight, not a design flaw.

I've also had two Twist 40's. The first got destroyed when I dumb thumbed it doing a knife edge too close to the ground. I flew the second for a while but decided I didn't like it. It wasn't a great 3-D plane but was light and floaty like the U-Can-Do. It's a great fun-fly plane to be honest. It just didn't "fly" like a plane should to me though. It was more this really light thing with a giant wing being pulled around by the engine. It can also be EXTREMELY responsive and fragile. People do love them though, it's all a matter of preference. Regardless, I do not think it is a good second plane.

When it comes to 3D, one of the OMP profiles or something like a Mojo will make the U-Can-Do's and Twists look a lot less impressive. I had the OMP Edge-540 and it is an excellent airplane for a good price. It definitely isn't a second plane either.