I bought the ARF that has the plywood spar between the two halves. I put lots of 30 min epoxy in and have never had a problem. I have let the local LHS owner use it and he has done rolling circiles, snap rolls (as best you can with the type of wing) and a lot of other aerobatic moves. It has hit the ground and cartwheeled several times, hit a catch fence 3 times, hit a limbo pole once with the left LE, flipped upside down on landing and other "great" moves. The wing is still together at the joint, it is probably 1/2 balsa dust under the covering by now, but the 2 halves are still together. One strong wing in my opinion.