My opinion on small hookahs is that they are not worth it... From what I've experienced, small hookahs never hit as smooth or good as the taller ones... I would never purchase a small hookah just because of the lack of flavor and smoothness that they bring... The first hookah I ever bought was a 33 inch, and I made that choice because I decided that I couldn't justify spending an x amount of money on a small hookah which was never going to come close in perfromance to the taller ones available... I'd rather have to wait a little longer to save up enough money to buy a $200 hookah, than to buy a cheap $30 small hookah right away...
I don't mind spending the extra money on a taller offering because to me smoking hookah is all about flavor and smooth smoke. If I can't get these qualities out of a small hookah, then I will stay away from it and spend some extra money on a taller piece which I will enjoy more and get more satisfaction out of... (some people are cheap though, and they want to smoke hookah and have fun while spending the least amount of money possible :
. I don't live life this way because the way I see it, you get what you pay for, and you gotta pay if you want to play.)
(everything I've stated above is my personal OPINION on small hookahs. I do not claim to know any proven facts of taller hookahs being better than smaller ones. But from my personal experience, I'd have to say that the taller ones are better and worth spending the extra money)