The first metal table I owned was a side table from a secondhand shop, black iron, wobbly on one leg, and it taught me that cheap metal doesn't mean sturdy metal. It rattled every time I set a coffee cup down, and after a year the paint chipped off the edges like it was shedding a skin. That rattle is the whole lesson. Good metal should feel solid when you tap it, almost dull, not tinny.
Finish matters more than people admit. Matte black is the easy one, it hides fingerprints and scuffs and sits well against almost any wall color, which is why it shows up everywhere. Brass and warm gold look wonderful in photos and show every water ring within a week unless you're the kind of person who wipes things down constantly, which I am not. Brushed steel or a pewter tone splits the difference, cool enough to feel modern, forgiving enough for actual daily use, and it doesn't scream at you the way chrome does under bad lighting. I avoid high gloss finishes now entirely, mine scratched from a single set of keys dropped wrong.
Measuring is where people get hurt, figuratively. A metal coffee table needs at least sixteen inches of clearance from the sofa, less than that and you're kicking it getting up, more than that and the room feels disconnected. For a console or accent table, leave room to actually walk past it, two feet minimum, and measure the doorway it has to travel through, because metal frames don't flex the way wood ones sometimes will if you tilt them. Height matters too, a side table should sit within two inches of your sofa arm height, not the cushion height, people measure the wrong part constantly and end up with something either lost next to the seat or awkwardly looming over it.
Metal tables sit best against softness, which is sort of the whole point of them. A thick rug underneath takes the edge off visually and sound wise, a wool throw draped over a chair nearby does the same job. They pair oddly with other metal pieces in the same room, two different finishes fighting for attention, so I'd pick one metal tone per room and let everything else be wood, fabric, or stone. Glass top metal tables look sharp in catalogs and show every smudge in real life, so budget for wiping it down or skip the glass entirely.
The mistake to avoid is buying one without checking the weight listed, a lightweight metal table looks the same in a photo as a heavy one and behaves completely differently the first time someone bumps into it.