After trying darned near everything over the years, I have settled on the beeper in point mode only paired with an Astro. Running silent with the astro was my goal, but it just isn't realistic. The astro can get you close, but looking at a screen while closing the final yards isn't an option. The cover we hunt is heavy. It isn't uncommon to have a dog 20 yards from you and not be able to locate it without a beeper.
Do beepers scare birds? Grouse and woodcock, no way, no effect what so ever. Pheasants, in my experience the beeper on range and point mode does. The birds seem to track the dog as it moves through the field and I get fewer pointed. In point only mode I honestly don't think it has an effect. Once that dog has that cock pinned, he's pinned and he knows it. I have not had birds flush once the beeper kicks on.
Do beepers hurt the dogs ears? Not as much as a bell does IMHO. A bell is below the ears and ringing constantly. The beeper is above the head and only goes off while on point. I also believe dogs have a harder time hearing the handler over the ringing of a bell around their neck. I once swore by bells, now I swear at them. Can't stand hunting behind a dog with a bell. But that's just me. YMMV.
Hawk scream = gimmick. No different than a beeper.