The vanity tray you choose will mostly depend on the style of the room where you'll use it and the tray size you need. It should fit in with the decor and be designed to hold the objects you want to put on it. Another consideration is the humidity of the room. A bathroom vanity tray that might get damp should be made of materials that can withstand moisture. A tray used on a bedroom's corner vanity table or dresser probably won't need to be waterproof, so there are more choices available.
In a bathroom, a vanity tray might be on a vanity table, the back of a toilet tank, a shelf, or even near the sink on a large vanity top. Where the tray sits is important when choosing the type of tray. One that sits near the sink probably shouldn't be made from natural materials that can be damaged if they get wet. Also, a metal tray that gets wet might rust or corrode, ruining the surface and possibly damaging the vanity it sits on.
A vanity tray used in a bathroom must be able to withstand moisture even if it doesn't sit near the sink. The humidity in the room from showers and baths can take a toll on some natural materials. A glass tray is a great choice for a damp area because it is easy to wipe off and won't suffer damage. A wooden tray, on the other hand, could mold or rot if it gets wet.
When choosing a vanity tray, the level of moisture in the room is important but so is the purpose for the tray. A glass or mirrored tray is a good choice for things like bottles of perfume. They reflect off the glass for a pretty look, and the flat surface is ideal for bottles. Conversely, a wicker tray or any material that is bumpy could prove to be a challenge if it is meant to hold items that need to stand up properly.
An antique tray can be a pretty addition to any room, but should probably be used in a bedroom instead of a bathroom. The risk of moisture damage, especially to a vanity tray that is very old, is just too high. With antiques or any surface that might easily be damaged, it may be best to avoid heavy objects or anything that can stain if spilled, like makeup or perfume. A pretty hairbrush, comb, or even jewelry can look attractive on an antique vanity tray without the risk of ruining the finish.