I've got one - my welsh x tb pony who is very sensitive and tends to sit behind the contact if he can absolutely loves it, it really changed his acceptance of the bit and we use it for jumping and XC as well. My fat tongued warmblood mare said "no thanks mum, not enough movement in this and it's a bit fat, please keep me in my verbindend and myler comfort snaffle" and my TB mare said "hmm, it's ok but I prefer my fatter loose ring with lozenge". The horse bit bank will let you have one on trial which is great as they're not cheap
I've got one on trial just now and will be keeping it! My horse was a little fussy in the contact and disliked any weight in the rein but with the Turtle Top he feels much happier and secure in the contact. Previously he was in an older NS loose ring snaffle with a lozenge (the ones before the Tranz Angled ones were brought out), I tried him in a Verbindend which was better but the Turtle Top is way ahead of both.