Plazma is plain awesome. I have yet to find anything that works as well, let alone better. Tastes great too. Haven't used any other Biotest products.
What sets Plazma apart for me is that even using small amounts, I find a noticeable difference in performance during training. I can start squatting feeling average, but if I'm sipping on Plazma while I warm up by the time I hit my top set I'm feeling great. Doesn't happen with other intra workouts I've used.