A bud of mine actually soloed his 10 year old son this summer on an UcanDo with a 50cc gas on it. 3D with 50cc, beginner, probably not but I’ll take a whack at the post. There will be slight difference in how the planes you mentioned behave in the air due to the different wings, moments, etc. However, the largest difference will probably be seen between brands as opposed to the model. I.e. company A’s extra may fly very different than company B’s extra. This throws a monkey wrench in the mix. That being said, from my experience, here are my observations. Keep in mind these differences are very slight, and not critical. Any quality 50cc sized 3D will fly all 3D maneuvers. Edges seem to excel at high alpha, probably due to the straight leading edge. They however can be a bit funny with yaw tracking and snaps. The Extras fly very clean, probably from double taper and a slight longer moment, but they don’t own any 3D category. Caps are spinning machines, but can be a bit squirrely at high alpha. The YAK, SU-26, and Katana I’ve never flown, so can’t really say. The point is, get what you like, check the 3D forum to be sure there are no major negatives on that specific manufacture’s model, then buy and enjoy!