Glass tanks are hard to maintain the proper temperatures and humidity in. They are designed for fish not reptiles, they are to open and can stress out a snake. This can all be worked around but by the time you get the tank set up you have spent far more time and money vs a tub or PVC cage set up. I prefer PVC cages because they are easy to maintain and also allow good viewing.

The larger the glass tank is the harder it will be to maintain. A 10 gallon isn't too bad but a 40 gallon is another story.

This is what I use: