I usually don't like bras without underwires because they don't give me a good shape and don't stay put. Uniqlo has worked some sort of bra magic with their wireless bras and even the bra tops, because they have a defined shape and stay in place really well. I think a lot of it has to do with the fact that they use firmer materials on the part of the wings right near the cups. Also, even though the gore on a wireless bra will never lay flat, the wire-shaped channels of this bra actually come a lot closer to my chest than in other wireless bras.
So comfortable I own three of these bras! It fits my extremely shallow/conical bust perfectly. The difference between the cup width and cup depth measurements is just ~0.5" on the XS, so these cups are really shallow but large enough to contain my volume. The band is stretchy and could stand to be a smidgen shorter, but it stays in place just fine. The only con is that the cups peek up above my camisoles from time to time.
Lots of fun colors and prints available, and gives a nice, smooth appearance. My go-to day-to-day bra.