I picked up a whole load of sheets of BMF at my LHS a few years ago. He was selling them off at the GBP equivalent of 50 cents each! I then used some of them to finish a Hasegawa 1/48 F-86. I first sprayed the whole model with grey automotive primer, and polished the whole airframe smooth. I then sprayed, and masked, the dark metal panels around the gun ports and tail pipe. When I came to applying the BMF, I found that so long as I took the process slowly, covering one panel at a time,there were no major problems. The trick is to use a piece of foil slightly larger than the panel you are covering, burnish it down, and trim to size.
I also found that, where I had to use more than one piecs of foil on a complex curve, that I could remove the wrinkles by burnishing with the blunt (rounded) end of a colouring pencil, and then, using worn 1200-grade wet & dry, polish the surface to eliminate the join line between the individual pieces of foil entirely.
I also found that, by sanding in different directions, using this worn 1200-grade wet & dry, I could achieve different effects on different panels. A coat of Future then made the model ready for the decals, and another coat of Future sealed them in, with the effects of the different metal panels still showing.
Since then, I've only used BMF for details such as chrome trim, rear view mirrors, and highly-polished panels on natural metal airframes, but , on the 'waiting to be built' stack,I've got a Revell (Germany) 1/48 P-47D and a Tamiya 1/48 MiG-15 bis which may well get the BMF treatment
Cute and cuddly, boys, cute and cuddly!