Funny you brought this up. I started my first reef tank 10 months ago and bought a Coralife 65 for my 55g. After my purchase, I started reading on here about how people have not had very good luck with them, overflowing issues, and simply not producing micro bubbles like it should.
Well, so far, all that I have read did in fact happen to me at one time or another. A couple months after it broke in and everything seemed settled in, it just decided to go into overdrive and it was overflowing water out the collection cup. Its only done this once, but that is quite enough.
Now for the past 5 days it has not produced any micro bubbles hardly at all so I bought 2 gallons of distilled vinegar and mixed it with hot water, put it in a 5 gallon bucket and let it run for 2 hours last night. Cleaned it all out real good and put it back on the tank. Before I went to bed last night it was producing waaay too many micro bubbles (which is normal when it gets upset) and had them all through the tank. This morning I woke up to find the skimmer not producing ANY bubbles.
So needless to say, I have not had very good luck with mine so far and will be on the market for another one. I think you will find a general concensus around here about this product.
And on top of all of that, I hear that it doesnt do a "great" job of skimming anyhow. I cant give you my opinion on it as far as performance because I've never used any other type of skimmer to compare it to, but it did produce nice skimate when it was dialed in correctly.
Good luck with your search.