waterfalls are great for snakes too obviously depending your snake and wether or not its small enough to fit inside any gap and get into the componants but assuming ur prb isnt a hatch it should be fine there great for humidity too
the only problems with the waterfalls that i found it that snakes do tend to explore and knock things around this is more of a problem with larger or heavier snakes, but they are amazing for humidity. although my 2 year old royal took the waterfall to pieces and stuck his head in the water bowl to use it as a second drinking bowl!!
they be a load of stuff in there and another water bowl for him to soak, so dont think hell go in the holes. hell be to busy, it will be aprilish ill be making a bigger viv and want evrything in it, so just getting ideas.
he will get in the holes, i got one for my Brb which is just over two feet long and he got inside the main body and wrapped himself around the pump! there is also a big hole to put the fogger into and my Brb fit into that too.... fortunately it had no water in, i had the sense to test it first which was lucky because the way it is put togeather, i couldnt take it apart to get him out without crushing him!!! i filled that with pebbles and it was fine from then on, but id wait until he's bigger. and on the plus side they look great in a nice set up.