I have a germgardian ultrasonic I like it it has a warmer to help warm the mist, I found that isn't really useful. The vaporizers work perhaps a bit better but cost more to run the steam they output is quite hot as well so location might be a bit more fussy. Get one with a large reservoir mine needs re-filling every 3 days bigger might be nice...
My snake room sits at 63% and my surrounding rooms are at 55% the screen top tank that is in my living room is at 58-63 no misting, no troubles, easy cheap solution. (I have a small rack too, exchanging one problem for another isn't a solution, racks can heating heating issues best solved by heating the room to 80ºF that can be costly for just a few snakes)
mine... I wish it had a larger water reservoir. I think they are all about the same? mine has been on for 8 months now it has not been turned off.
http://www.onestepahead.com/catalog/...mpaign=product