I use one when doing fast work/hacking in company as pony tends to get a bit onward-bound! I did use a pelham but actually found that going back to a snaffle and using a drop works better. If you're not experienced with fitting them though you NEED to get someone who is as you can do serious damage if it's too low
I've just put my boy in a drop. He's going really well in it so far. Its very loose, to the point he can still happily scoff his hay whilst wearing his bridle!! I do like it, and so does my boy. Very pleased I tried it!
I've just bought one and tried him in it last night out hacking.
Noseband was quite loose and he seems ok in it. Wouldn't use it for fast work as it can impact breathing but hoping to use it for some schooling as he hates a flash but does have a habit of trying to evade the bit.
I like them. If it is fitted correctly then it shouldn't impact on breathing - it needs to be fitted high enough and be a decent make that has those metal spurs inside to keep the bit over the nose "up" (the cheap ones like Robinsons etc always fall down over the nostrils because they aren't constructed properly so don't stay in place).
Used one for my last horse. They're great for horses that don't like pressure around their jaw. I used it tightly enough to stop him opening his mouth wide, but loose enough that he could still mouth the bit. If you have it on "very loose" then what effect is it having? I'd like my new one to go in a drop because I do like them but he detested it when I tried. Much as it galls me, he only likes a cavesson and flash (I hate flashes generally!). With last horse I've used it for all sorts of things - DR, SJ, fast work, hunting a couple of times (haha... went back to the grackle for that!), hacking.
my two racers much prefer them - both fought a flash but settled in a drop - one used mainly because the mare was so sensitive that any movement on the bit led to a head throwing tantrum where as with a drop it seemed to keep everything a bit stiller
Genie prefers a drop! Initially had her in a flash but in hindsight wish I'd changed to a drop so much sooner. I think she finds it gives her a clearer signal than the flash and she's a very 'black and white' horse in her instructions. It's either right or wrong in her opinion!
I personally love them as you can use a less harsh mouthpiece and still get the same effect as a double noseband and a harsher mouthpiece.
HOWEVER it all depends on the horse. I had horses who went perfect in them, and others who hated them. My current horse really doesn't like drop nosebands so for now mine is stored away.