In my experience with FPV freestyle, the frame of a quad is not very important in terms of flight characteristics. So long as it has a reasonable shape and weight distribution (particularly top-mounted battery), a frame will fly fine. When buying a frame, I care mostly about the following:
- Ease of maintenance
So far my go-to frame has been the qav 210 clone in its many incarnations. You cannot beat the price ($20 or less). It’s a pretty simple frame: unibody bottom plate, six standoffs, top plate. The main drawback has been durability. The plates break relatively easy, which isn’t a big deal to me because they are cheap and and easy to replace.
I recently found this “qav210 style” frame from Valuehobby which is almost a clone of the Astro X X5. The main difference is the unibody bottom plate, which I much prefer. At $20 it was an extremely good deal. It fixes the durability issues of the qav210 with no drawbacks that I can think of. See my video review for more.