Personally no, as I think it would just clash and look very silly on my M/W piebald gelding. But I do think its fun and some of my friends would love it!
Personally I could take them or leave them - BUT what happens with cleaning them? And how tacky will it look when all the diamante starts falling out as it undoubtedly will?
I personally think they are fun, jazz things up a little and why not. I feel too old for that sort of thing. However I dont mind seeing it on other peoples
I have a diamante browband which I like, personally I would think the martingale is just a bit too much but see at the end of the day, if you like it and it's what you want - get it, who cares what anyone else thinks!
I wouldnt touch it with a bargepole, just not my style.
But, if you like it and (most importantly) need one on your horse then why not?
Bit of diamonte isnt going to do him any harm.