Measure the apron depth on your tabletop before you order anything. Desk legs mount to a flat board or slab, and if the top has a lip or a frame underneath already, you are drilling into wood that is not there, or fighting hardware that does not sit flush. It is a five minute check that saves a return. Once that is sorted, this is one of the cheapest ways to turn a leftover board, an old door or a cut piece of countertop into a desk that looks like someone meant it, not like a family inherited a plank.
A plain wood or laminate top with a set of metal legs sits well in almost any room that already has mismatched furniture, which is most rooms in most houses I have been in. It reads like a decision rather than an accident when the legs are a clean shape, hairpin or straight tapered, and the top is wide enough that the proportions do not look spindly. Where it falls apart is next to anything heavy and ornate, a carved sideboard, a dark traditional dresser, ball and claw feet nearby. The thin metal starts looking like it wandered in from a different house and got stuck there. It also struggles in a room where everything else is upholstered and soft, a desk like that wants hard surfaces around it, a lamp with a metal base, a chair that is not fabric. If someone has none yet and wants one set to start with, go with a simple adjustable height leg in black or raw steel over anything brass or patterned, because the plain ones disappear under whatever top you eventually swap in, and you will swap the top eventually.
They hold up better than the top usually does. The legs themselves rarely fail, it is almost always the tabletop that gets the coffee ring, the scratch from a laptop corner, the dent from someone setting down a cast iron skillet for reasons nobody can explain a year later. After a move, the legs unscrew in minutes and travel flat in a box, which is more than I can say for most real desks, which arrive at the new place scraped along one whole side from being wedged into a truck sideways. One set I put under a cut down countertop scrap has been through two apartments and a kid doing homework on it every night for a year, and the only casualty was a sticker that would not come off the surface, not the legs.
Measure from the floor to where your knees need clearance, not just the finished desk height, before buying a fixed length set.