I just wonder as my LFS has some beautys in, often thought about these and read about them but when I think of dedicating a tank to them I just wonder how interesting they actuallu are?
How long is a piece of string? some people find snails extremely interesting, others see them as a pest, each to their own.
They are fairly active, similar to a betta they like to rest quite a lot and have bursts of effort although it is also down to personality. I would get one and try it you can always take it back if its not active enough for you.
edit: As you are such an oddball lover perhaps an olm (Proteus anguinus) would be suitable, I would give a hand to keep one of these they have to be the coolest and most extreme salamander.