Sicce are quality pumps. There are a lot of pumps on the market across many price points. You are asking about the Cor 15 and owners opinion and/or experience, correct? If so:
I run 3 Cor pumps. 1 x Cor 20 return, 1 x Cor 15 return, and 1 x Cor 15 skimmer. I went with the same manufacture because I wanted to be able to hot swap should one fail. I can always take the skimmer offline. They all use the same fittings at the output so this makes it really easy.
Cor 15 and 20 are running return lines. Redundancy. The 20 is on the longest plumbing line and both connect up to 1" sea swirls. All plumbing is 1". Hard plumbing. Looking at it now I should have went with 1.25" plumbing and reduced down at the Sea Swirl for better performance. I also think that is the recommended size anyway. I already had everything plumbed so it is what it is.
With regards to noise I do not notice it and the display is in my office where I work daily. I do hear a slight hum when they are dirty and clogged up with Strombus snails. I'll take one off line, make a bucket of citric acid, and let it soak for a couple hours. Brush it, rinse it, put back together and it is fine. I think to make it super quiet then using 1 or 2" of silicon tubing before hard plumbing is idea or so I've heard.
Longevity - I've owned them all since launch to general public. Maybe a month after due to availability. I've had no issues with the pump - any of them. They are heavy, well built, and work for me.
