Coralife Skimmer are considered decent, reasonably priced skimmers. Many people, including myself, have reported some problems getting them adjusted to consistently skim well. THey can be finicky but offer good 'bang for the buck'
If you post your tank size and whether you have a sump with the possibilty of an 'in sump'
skimmer people at this forum can give you more advice.
If you are going with 'hang on the back' (HOB) skimmers..check out the Remoras. More money, better skimmer, IMO.