I've got 2 flying, Aircombat Zero and .45 size Miss America P-51, and 3 more waiting for assembly. I've found they are built well, finished well, and fly great. Are they perfect, no, but for the price they are quite a good value. The retracts on my P-51 have done ok on grass so far, but it's still quite new and doesn't have many flights. It would be easy to change the whole unit, or just the struts. I guess permanant gear could be installed, but that seems to take something away from a Stang or Spit.