coralife skimmer

[bv_reefer]

I've narrowed it down to getting a coralife hang-on skimmer in a few days and want to know the pros and cons. i know it's a very popular skimmer and widely used. few questions though. Which one should I get for my 33-gallon mixed reef, the 65-Gallon rated skimmer should be enough right?
Also I've heard something about how they can clog or flood over, why and how can i avoid this? Also how much gunk would they pull out, enough for my tank?