I got this "binder" recently. I like it better than any one I've had so far (I'd estimate that I've gone through about eight from various brands).
Pros:
-Very breathable, can exercise in it without feeling like death
-Not terrible in hot weather
-Doesn't show under a lot of shirts, though if you have a shirt with a wide neck it'll show, but does look like an undershirt as opposed to a bra since the neck is high.
-Helps with hiding hip fat
-Feels natural. I forget I'm wearing this sometimes. Probably would be fine sleeping in it as well, though it's good practice to take breaks.
Cons:
-If you have a bigger chest this isn't gonna do the best of jobs binding since it's got less compression than a typical binder. It's still not the worst option in that case, but you won't look completely flat. It's worked well for me flatness wise.
-I wouldn't wear this by itself because it doesn't fit like a regular shirt. Definitely looks an undergarment.
-It smells like a McDonald's playground right out of the package. I recommend you add baking soda into the wash to get the smell out faster.
-I suspect this will stretch out the longer I use it. The solution is to dry it on low as opposed to air dry it. It's got cotton in it so it'll shrink.
I recommend you only get it in black or white if your concern is passing. A lot of cis men will wear undershirts (typically in white, sometimes black, but never in nude).
If you're in-between measurements, order a size up. I made the mistake of getting a size down and I wasn't even able to get it over my head. Had to exchange it which took a while.
If you're interested in a binder with flatter coverage I will post a review of the underworks ultimate binder if requested. Underworks is by far my favorite binder brand for many reasons.
1 month update: it still works well. Am happy with my purchase.