I have the Fly Eagle F-15 and its a very solid built jet, from what I have seen in mine and from the other builds I have seen it does not need any mods to make it safe to fly. I have compared it to the fei bao and I like mine better as far as detail/design, the honey comb is light. My F-16 required no mods to fly and I have flown the heck out of it, pulled some hard g turns and pull ups with no issues. I have had one nose gear door air cylinder leak and the newer generation gear are holding up much better. They are coming along and continue develop their stuff and as stated above all the jets makers have pros and cons you just have to weigh them and see what your willing to deal with.