The moment I'm glad I own one is every single morning I open a closet door in a house built in 1954 with exactly one tiny closet per bedroom and somehow find a shirt that isn't wrinkled. Old houses were not designed by people who owned clothes, apparently. An armoire fixes that in a way that still feels like furniture instead of a problem you're apologizing for.
That said, I wouldn't put one in a small bedroom without measuring twice and then measuring again, because these things are deep, often two feet or more, and they eat floor space a built in closet never would. They're also the wrong call if you move often, since a solid wood one can weigh as much as a second person and getting it up a narrow staircase is a two person, several swear words kind of afternoon. Color wise, I'd steer toward a warm wood tone or a soft white over anything dark and glossy, because dark finishes show every scuff and a glossy one in a bedroom reads a little like a hotel conference room. White or a pale wood also tends to make the piece feel lighter in a room that's already working hard to hold a bed, a dresser and whatever else lives in there. Where it goes wrong is next to anything else large and dark, a heavy dresser or a big dark bed frame, because then the room stops being a bedroom and starts being storage units stacked in a corner. It also doesn't love a room with low ceilings, since most armoires are tall and a low ceiling makes them look like they're wearing a hat that's too big. The difference between a good one and a disappointing one is almost always in the back panel and the doors. Cheap ones use a thin sheet of fiberboard for the back that bows if you hang anything heavy, and the doors don't sit flush, so they swing open a little on their own, which I found out the hard way with a floor model that looked fine in the showroom and looked like a haunted house prop within a month. A well made one has real hinges you can't see wobble, drawers that don't rattle when you shut the door, and a back panel with enough substance that it doesn't flex when you knock on it. Knock on it. Nobody will judge you.
Next to it, I'd put a simple bench or a slim chair, something low, so the armoire stays the tall piece in the room and doesn't have to compete with anything else trying to be tall too.