I love the Exo-Terra terrariums. They have a better latch system and come in more than 3 sizes. Two doors helps out with quick little frogs and keeping air moisture in when doing hand misting. You can find them in most pet shops, so easy availability. (I voted Exo-Terra.)
Zoo Med terrariums work well for many reptiles since you can use dome fixtures for additional heat support. Their use for amphibians is personal preference. I help a friend set one up, I was not that impressed. I may purchase one for a GTP's since I can use the dome heat fixture for ceramic heat emitters. Many pet shops carry them so this often influences the use between Exo-Terra and Zoo Med terrarium.
Aquariums are always nice. Most people have had fish at some time so you can often find used ones cheap or even for free. I acquired a nice 55g acrylic from a buddy. It was free! Garage Sales, nearly new shops, and classified there is easy access to aquariums.
Custom tanks take time for production. You have to plan in advance your terrarium and wait for delivery. I know I like to just run to the shop pick-up a tank and have a nice weekend or week project instead of wailing a 1-2 weeks for production, then 1-2 weeks for delivery. I really don't like the wait, and I see additional cost as an issue for widespread use. I hope to custom build one myself this summer.
Later and Happy Frogging,