I have never met one person in the gym that does HIT training. haha, the majority of them dont even know what HIT is. Care explaining this a little bit more? 
there are different type of HIT programs...if you have watched dorians blood n guts vid you see him doing a few what he calls warm up sets...then you see him do his one working set...this would be with the heaviest weight he can handle to failure and beyone...the reps are done with strict form in a slow and controlled manner...after a set like that, especially if you have a spotter and take it beyond failure, you are done.
i agree that medium volume training should be used also from time to time...but i think high volume is a waste of time.
heres a quote from dorian on HIT...
"It is the intensity of the exercise that is important not the duration. If you do one set that is adequately intense enough to stimulate any muscle, then you are not going to gain anything, even if you do 99 or 100 such sets. If you do one set that is intense and to failure, then you have triggered the muscle growth.
Doing another set at that point is not going to give you any more. It is just going to make it more difficult for your body to recuperate. So that is the reason for doing fewer sets."