Man Made Live Rock
Power heads are needed for all sorts of reasons from in tank circulation to mixing up a batch of salt water. Yes, I know about the drill and paint mixer way, but most people just use a power head. Here again I have had to go on a trial and error excursion. The best thing I can tell you here is that cheaper is more expensive in the long run than getting good ones the first time around.
Many power heads seem to be built on the disposable theory. That being that if they build it to break, you will buy another one of theirs and round the circle you will go. The sad part is that often this works in their favor. Many people simply do not get the idea that 4 to 9 months is Not the normal life span for a power head. More like a couple of years until it needs to have it's impeller assembly replaced.
I have tried a number of different power heads and there are two that I would not hesitate to buy and those that I currently have. Maxi-Jet's and one found at my local PetCo that is named Profile. Both of these are quality and will go a very long time needing only cleaned on occasion.
I used a Profile to circulate water in one of my Man Made Live Rock curing tanks not on just one batch, but three! I finally had some mercy for the poor thing and replaced it with one of the lesser quality power heads that had started to make an awful noise due to poor manufacturing. I figured I could stick it in there and leave it until it died as that particular brand was not known to dump chemicals into the water upon failure unlike an unmentioned top brand name power head. The good thing is that the last time I pulled that Profile into service it fired right up and did not appear to be missing any pressure and I had put it up without cleaning the scale off of it!
I know there are some of you that simply wouldn't get over it if I didn't mention that there is a top of the line power head made by a European manufacturer that would likely still be running 50 years from now. I have nothing bad to say about them, if you have the money for them by all means get one or a few, they will serve you well. For those that can't or won't afford them the two I name above should serve you well enough for their cost.