I only drink Solyent a couple of days (nights, really) per week.
I work a couple of nights per week, and my workplace doesn’t really have convenient food storage or prep facilities available after hours. Soylent is much simpler than preparing ahead, and there’s a lot less to carry; only the sport-bottle I use and my partial-packet of powder.
I usually just drink it plain, but sometimes (about 1/3 of the time) will add some essential oil for flavoring. I was experimenting with cake flavorings, but they weren’t strong enough.
I use DoTerra oils, but Whole-Foods has some good choices as well. Be sure to select types that are labeled as edible; the others will upset your stomach. I can carry 4 or five bottles of oil in a zip-lock, and then I have a variety of choices–including plain, of course.
Some good choices are frankincense, lemon, lime, orange, peppermint, cloves, rose-petal, and lavender.