As far as we know, birds aren't great connoisseurs of architecture. The important thing is that your feeder works properly and allows your featured friends access to your seeds. You may even want to try your hand at building your own feeder or birdhouse. There are all types of plans available and, of course, you can design your own from scratch. If you plan on building something more elaborate than a simple plastic feeding tube, building materials become important.
Wood is usually the best choice.
It's easy to work with and maintain. More importantly, though, it doesn't radiate heat as much as metal and some plastics. This is an important consideration for two reasons. First, some fat-saturated bird foods like suet cakes will turn rancid very quickly if exposed to heat. Secondly, if you are building a birdhouse for nesting birds as part of your feeder, building from wood will minimize the heat build-up within the birdhouse.