!/8 inch glass may be cheaper, but it's fragile to knocks by rocks, ceramic bowls, et. Most places where you buy 1/8 inch glass will be able to see you are an amature and hopefully try to talk you into the next thicker size. The minimum glass spec should be 3/16 tempered, or a laminated version of a glass panel. It takes an expert and diamond tools to drill, cut openings into, and make inside corners in the glass panel. Those cuts would be made before tempering, and an unsufferable percentage of such machined glass spontaneously fractures during tempering. Even plain rectangular pieces shatter, which is part of the reason tempered glass costs more. BUT
If you use glass properly you will be happy with it. And, if you handle plexi properly, you will be happy with it also.
There is only one major problem with glass, even if you use the sturdy 1/4 inch size. It can be shattered, the shards possibly causing serious wounds to life that is standing by. I've been a residence repair/builder person (licensed in CA) for over 45 years, and I've seen it all.
Even glass bends, and an uneven structure causes distortions similar to what the disgruntled ex-plexi users (I'm not talking about you, whoever you are, it's more about how information flows) complain about. With plexi, you can get away with much more inaccuracy in the structure. I've always applauded low-tech, Saturday-afternoon builders, because they have the guts to tackle the project and plan to be happy with the product.
Happy building, y'all.