Depends on how balanced those other meals are. There are some nutrients in there that are not in every ordinary meal, like methylfolate. You could think of soylent as a weak multivitamin plus macronutrients. In an early report a tester talked about a fantastic energy boost, and I'd wager he was deficient in one of the nutrients soylent contains. In the case of methylfolate, it's actually better than most multivitamins which only contain folic acid, which is harder to metabolize (especially if you have a MTHFR mutation).

I like the Coffiest product because it's basically like green tea, due to the caffeine + l-theanine they add (basically you get calm energy). Also I have only 13 minutes from waking up to leaving my door each morning, so saving time from mixing anything up, chewing food, etc is very useful.