Soylent has been shipping awhile, and although the pundits are having fun with it, you don't see many people talking about their experiences. So, in the interests of deciding for myself, I bought a week's worth.
I'm done with 3 days of it so far. As far as taste goes, it's bland. Not bad bland, just bland. You can spice it up with chocolate or vanilla, but it really doesn't need it.
More importantly, it's incredibly convenient. It takes less than 5 minutes to make a day's batch, and from that point, you just pour. It will never replace pizza or Mexican food for me, but half the time that I make a meal, I really don't care what it is. I just want something to eat. Soylent fills that gap nicely.
Some niches where it would work very well: disaster relief (as long as you have water), backpacking, survival planning. I'm sure there are others.
As for me, I'll keep some around and use it to supplement my diet. I can easily see it replacing breakfast and lunch for me fairly often. #soylent