Stop N Turn bit (hackamore?)

So I finally had someone come out and work with my horse. I originally ride him in a Dr. Cook's Bitless Bridle but he has been starting to push right through that (ignore whoa, turning, head tossing, etc.) The trainer put him in a stop n turn "bit" and he rode like a dream. (I tried putting him in a snaffle before and he kept mouthing it and pulled through that as well).

But then I went and read opinions on it and heard it is very harsh and a lot of people would never use those. Well, anything can be harsh in the wrong hands right? Anyway, my homework today is to ride him in it again and see how he does but if it's like yesterday, then I might purchase the stop n turn "bit". I just want to know what you all think of it?

The metal piece goes under the chin (loosely) and he had the noseband vet wrapped to avoid rubbing.

SS Stop N Turn Western Bit - Horse.com