For what they cost I'm a big fan. I have two of them, one came with my 28g nanocube and another I bought for my frag tank. They are both the duo model which allows you to have alternating currents as frequent as every 6 or 10 seconds (sorry, can't remember for sure). The one draw back is that one of the wavemakers doesn't power back on correctly. So if you hook it up to a timer to power it off at night, when it powers back on the powerheads will no longer be alternating. You have to turn the dial to set the frequency to another setting and then turn it back to get it back to alternating again. I have read other complaints about this problem, so it doesn't sound like it's just a faulty unit. The one I have on my frag tank that works during a restart is newer but has the exact same model number as the one that doesn't restart properly. I'm going to guess it was a design flaw that they may have fixed at some point. That being said, if you intend to hook it up to a timer I would definitely make sure to avoid buying a used one - especially since these are about the most affordable wavemakers you can find. One other thing I wish it had is a feed mode.. but what can you expect at this price point? The red sea wavemaker pro is probably the cheapest wavemaker with a feed mode at $160.