I'm running the prism HOB with the upgrade kit (surface skimmer & media basket). For my 40G tank, it's been good. I did have to modify it a bit by adding a 2 inch piece of rubber tubing between the body of the skimmer and the collection cup and a slightly longer piece of airline tubing. Doing that allowed me run the skimmer at full flow all the time. It does collect some very nasty stuff, it almost makes me puke when emptying it.
http://www.jlaquatics.com/phpstore/s...duct_ID=ps-rsp