I have a pair of Cor 15's. One for return, one for skimmer. This way I can swap them out with little to not downtime say if my return failed. Skimmer can be taken offline for a bit. They are built F-150 truck tough if you get my meaning, really they are. The block is super think. I've had one for about 5 months the other maybe 4. Like a few said they are relatively new to market (retail anyway) so we can't answer reliability yet. I'd be lying. But so far it seems to be holding up pretty good for my 210 gallon tank and LifeReef skimmer.
I was going to go with a Vectra but after reading some of the failures, which I believe they have since corrected, I ended up with the Cor since it fit into my ecosystem. I will say if you want reliable, and not really a knock per say, I would avoid Jaebo DCT series. I originally was planning on using the 15000 series, and actually ran it for a leak and plumbing check before moving the tank into the house. Upon taking down and prepping the tank for movement the handle on the Jaebo snapped off. Ok, no big deal not like it is really a handle although it looks like one...anyway, few days later I was attaching plumbing when I noticed or felt the return line neck separate from the motor body. I mean that isn't normal right? So I checked again and sure enough right under the threads it was cracked or pulling apart. On top of that the body of the motor or housing unit is paper thin. That is when I said ok just get something else.
Don't get me wrong I had RW's from them for several years with good success. I'm just not a fan of t he DCT line of pumps based on the one I owned. Cors so far, so good. Others gave great suggestions as well. Best of luck.