I have used both PRE and intrablast before.
PRE is still my gold standard for a product that does not contain any exotic stims. If money was no issue, PRE would be the only product I would buy and use in this category. I workout about 12-15 hours after my last meal and PRE has everything I need to crush my workout and has never caused me any issues when it comes to my stomach or post-workout. I like how everything included in PRE (including the kitchen sink) is there for a reason and backed up by science.
For intrabast, I have only used this product a few times in the form of sample packets that I received from the PricePlow website (both the regular and natural versions). I like how NutraBio was providing a complete EAA product quietly with this before all the hype hit the market about BCAA vs EAA. In terms of the results with the product itself, there is no question this extends your endurance and output for as long as I have ever needed without needing to intake solid food. I have used this intra-workout when my pre is not as complete as NutraBio PRE. My preferred way to use Intrablast though is during a round of golf. Since I don’t eat before hand, I need a product that provides me with fuel, energy, hydration and focus. I will start with a scoop before the round in 32 ounces of water and sip on it the entire day. Sometimes if I am feeling run down after nine holes, I will through in another serving (or half serving) at the turn to get through the rest of the day. I have especially found this effective when it is really hot outside and I am standing in the sun for multiple hours. Never had a hydration issue on the course when taking this.
From a consumer standpoint, I am thrilled to see that Intrablast is a 30 serving tub (at almost 25g per serving). I think many other companies who created a product like this would go the 20 serving route. I only wish PRE was also available in a 30 serving or more container.