In my opinion, the best, and my favorite Pre all time (that's still available) is God of War Red which is Amp-Citrate...however, other pres I have used with Amp-C have been very close. The problem is they are becoming obsolete.
I have not used a "heavy hitter" pre in a long time. I took a big-time break from them, and currently, believe this or not, my go-to favorite set up is Focus-XT. Enough of a caffeine boost, and enough focus for a great session.
The weirdest thing is, contrary to most, when I sued Focus XT in the academic setting, after a while I would crash hard and feel weird and kind of like sh*t....but....when I use it pre-workout I just have a great gym session no crash no feel like garbage...IDK