Got mine yesterday. I was looking for an extra boost to my TT (with standard carts) in regards to both vapor and TH. Basically, something similar to what you'd get with the LR atty but with more shelf life and without the occasional burnt taste.
Heres my impression:
I got my extra boost and them some. At 90%, it seems much more powerful than a LR atty without the booster. Additionally, I only have draw for about 2 seconds and I get a better vap and TH I normally get after 5 seconds or so without the booster. And I got a head rush and slight buzz, something I experience only a few times a year with analogs. I didn't experience a burnt taste. Had a analog after hours of using the TT and booster, and than analog didn't even match - felt weak really. Genuinely surprised and impressed with this device. My only issue is that I wish the dial had little clicks or checkpoints along the way, not only so you know where you are, but also so it stays in place. it's really loose and turns very easily.
I also purchased the 1000Ma battery, which did make it very long. I noticed that my old standard tornado battery worked much better than the mega, and it was quite noticeable. Much less effort to draw and better vapor and TH with the standard battery. Doesn't make sense to have poor production with the mega battery but it was a big difference for me.