Supplier
Glass Cages is a reputable supplier. The basic tanks are economical, and they do alot of custom work.
Glass v. Acrylic
Glass is heavier than Acrylic
Glass is more scratch-resistant than Acrylic
When glass is scratched, you can't repair it, Acrylic can have the scratches buffed out.
Glass will deform less under stress, an Acrylic tank will bow outwards when full, but this is not a sign of damage.
Glass is harder to drill than Acrylic, important for some tank mods.
Glass is cheaper than Acrylic.
Glass will break easier than Acrylic.
The decision is yours. I'd go with glass unless:
a) the tank will sit in a high traffic area and may get bumped alot
OR
b) the tank is very large and weight is a factor.
OR
c) you're planing on doing alot of drilling yourself.