Actually, I have found the helicopter gunships with armor and two targeting computers (with the obvious upgraded weaponry) are relatively good at shooting down fighters, or at least better than any other load out I have found.
The armor slows the airspeed, increasing(slightly) the time between when both ships start shooting at one another, and when the UFO closes to point blank, the game lags insanely, the UFO massively outmaneuvers you, and you get your face eaten.
Two helicopters, maybe even two saracens if that's yer poison of choice, or even one heli and your transport can take down a fighter with minimal chance of losing.
A single craft equipped as stated above still weighs in favorably against the fighter.
You can not outfight UFOs point blank without advanced craft. We all know this. Sure, sometimes you get lucky, but your chances even then come down to how damaged the UFO is when you get to point blank.
As such, the benefits of "going all in" on downing or reducing to a sliver of health that UFO fighter before it closes, including reducing your own velocity, seem to outweigh the obvious drawbacks. Don't get me wrong, your helicopters spend a lot of time in the repair shop, but that is time they are not spending in a flaming wreckage strewn across the Russian countryside.