like any mechanical device they have their pros and cons. (mines a 125 I dont know how different the designs are so this may or may not be usefull)
Pros, work well for skimming, not super expensive, tough, good powerheads. easy to clean, easy to dump, reliable, pre installed overflow drain line for draining into a larger receptical, (I now drain mine into a 3quart specemin container) as opposed to the regular collection cup.
cons, can overflow easily, if you make an adjustment the full impact may not be noticed for several hours (aka after you fall asleep) Dont run it HOB style. I nearly lost my tank due to an overflow problem.
bubble diffuser is crap, run in sump with your own baffels throw the diffuser in the trash.
air intake silencer plugs easily (throw away make your own out of an asprin bottle and a cotton ball.
air intake line builds up salt quickly at the injector tip.
thats my take on them, I have been running the coralife SS 125 for over a year.