Since you asked for my opinion:
First thought: Damn, those're expensive.
In more detail, this product is analogous
5-hour energy and similar "energy shot" products, which, if you really want to, you can get at any drugstore, gas station, or supermarket for a couple dollars apiece. That's my economic standpoint. It's a marketing gig, in case it weren't obvious. The kind of thing you would buy for novelty.
Red Bull comes in 8.3 ounce cans. One can has approximately 80 mg of caffeine. A 12-oz Mountain Dew has about 50 mg of caffeine, a Dew Game Fuel has 72 mg, and a can of Coke has about 25 mg. The caffeine of coffee varies depending on preparation, but you're looking at an average of 100 mg per 8 ounce cup. Typical caffeine tablets have 200 mg per tab.
As for the "nutritional content" of the product:
The B-vitamins aren't likely to have toxic side-effects, even at very high doses. They also aren't likely to do anything beneficial, because B-vitamins are water-soluble and you're going to end up dumping all of the excess out in your urine. B-vitamins are important for energy metabolism, but they're also in everything. Most grains are fortified with B-vitamins, including breakfast cereal. Very, very few people have legitimate B-vitamin deficiencies. Extra B-vitamins will not make you more energetic.
The "enzyme blend" in the product is presumably being touted as aiding in the metabolism of whatever energy stores you have or whatever food you've eaten. Amylases break down carbs. Cellulases break down indigestable starches (cellulose) found in plants. Lactases break down milk sugar (lactose), lipases break down fat, and proteases break down protein. The claim is that by putting these things into your stomach you will better digest anything that's in there and get more energy. The even more far-fetched claim is that by consuming lipases, for example, that you will break down stored fat in your body.
This is all wrong. Enzymes are proteins. Proteins are rapidly digested and broken down into component amino acids in the human stomach. Those enzymes will suffer the same fate as any hamburger. And they won't do anything in the stomach because enzymes have very specific pH requirements; it is unlikely that they will be active in the acidic environment of the stomach.
There are exceptions to this; it is possible to take lactase capsules to overcome lactose intolerance, for example. But this works because the lactase is protected by a coating to allow it to survive the stomach and reach the intestine. Lactase suspended (not dissolved; proteins are not water-soluble) in some liquid is going to get chewed up by gastric proteases, as are other enzymes thrown into the stomach.
L-taurine is an amino acid that might have some stimulant effects. Glucuronolactone is a by-product of glucose metabolism in the liver; it is touted as a fatigue-fighter, but there's not a lot of evidence to support this. And of course, there's a lot of caffeine. The majority of the stimulant effect of this product
will come from the caffeine, which means that it will have the exact same effects--and side-effects--as heavy caffeine use, such as tremors, anxiety, heart palpitations, increased blood pressure, and insomnia.
Coffee, without sugar or cream, doesn't contain carbohydrates, fats, or proteins. As such, it is non-caloric. So if you really want a low-cal caffeine fix and you think popping Vivarin makes you a junkie, drink coffee.
If you don't like coffee and really want a no-cal caffeine fix, and you don't want to pop caffeine tabs, uh...you're out of luck, I guess. You could always switch to...er...diet Mountain Dew?
Or you could shell out for overpriced "energy shots."