sorry ahead of time for the wordy post:
huge fan of erratic and vitasport. higher stim at 300mg caff anhy per scoop, you'd pry be fine with 1/2 scoop. IMO, way better than any other off the shelf basic pre workout, tastes better than C4. I quit using it because it is a little expensive at nutrishop. I'm 6'1 210, caffeine fiend, erratic gave me a slight rush but mostly clean steady energy and good pumps. I never had to use 2 scoops so the 40 serving container lasted me a while each time.
it doesn't matter if there's a proprietary blend or not, nobody truly ever knows what's in the product but FYI, labdoor.com (no affiliation, not an advert, useful informative site), they test mainstream supps for label accuracy and harmful substances. It blows my mind how many products are nowhere close to what they claim, unfortunately erratic isn't tested yet on there, mostly mainstream ***************** products.
I read what other guys said and agree loads of stim aren't the best for overall health, especially the heart. The more I learn and read about all these pre workouts, the more I want to buy bulk raw ingredients and make my own at the proven dosages and ween off of the caffeine, or use coffee or green tea. way cheaper in the long run too. I just like ots pres for taste and convenience. I wouldn't recommend it to you if you're stim sensitive. It also wouldn't hurt to ask the guy for a couple samples, I'm assuming this is at nutrishop because that's the only place where vitasport sells their products.