I have tried the following with the following results:
BSN No-Explode = Excellent (especially fruit punch flavor) - use it as my first choice pre-workout drink. Prvides great pump, and improves energy and concentration.
Gaspari Superpump = Utter shit, did nothing for me whatsoever. Don't know why people rave about it.
Musctech NanoVapor = Not too bad but it's effects are too long lasting and kept me awake at night - reasonably good stuff though - woul use it again depending on what price I can get it for.
VPX Shotgun = Also very good, would use this as an ideal replacement for No-Explode if it wasn't so pricey. Flavours taste nice too.
Dorian Yates NOX = provides good energy and improves concentration levels but tastes like vomit and the pump I got was average.
I once combined No-Explode and Superpump in the same workout a few weeks back and the workout I had was incredible - strength and power shot through the roof and I was high as a kite for the whole workout!
