FYI lilkitty90, that "argentine snaffle" is not a snaffle at all, it's a curb bit.
snaffle means the bit works on direct pressure, curb means leverage. because that bit pictured has shanks, it is a curb bit. in addition, it's rather harsh because it combines nutcracker action with poll pressure. in the right hands any bit can be mild, but it's really a matter of what the horse likes, and the education of the rider's hands. please note - i pass no judgement on your horse, hands, or riding, as of course i've not seen you ride, and you say your horse loves the bit so hey, if it works and the horse is happy, then i've got nothing to add :)
to the OP - my TB that i hunt is incredibly strong, standing near 16.2 and weighing in around 1400 pounds. he's fit and feisty, and while finished and incredibly responsive, there are times when fully body effort is needed to slow him down in the hunt field. he's very sensitive in the mouth, and a single jointed snaffle is out as he hates them, and more than one joint he finds distracting. i found great success with the myler 3 ring (limited poll pressure) with first the level 2 mouth, then the level 3 (for finished horses). he loves the bit, the nose pressure cues him when i need to get his attention without hauling on his face or taking every bit of my seat and back and legs and body weight, and he's incredibly happy in it. for anyone doing aggressive equestrian sports, i can't recommend these bits enough!!! the mullen pelham was just all leverage (since obv the no port smooth mouth was as mild as you can get) and frustrating for him and me. once i made the change to this bit, we're BOTH happier!
please note - this bit is NOT a shortcut for training, useful for correcting issues, or a quick fix. it's designed for a horse that already is light on the aids and fore, but is intended for a horse that is physically fit and strong.