Owned a Cort Curbow 4-MR 4-string bass for a while. One of the fastest necks I ever played. The only other neck that was faster was on an old Hagstrom bass back in the early '70s.
Very modern sounding active bass. I never completely sussed out its control set to my own satisfaction, but if you like it funky, this little bass, with its Bartolini pup, will deliver it in truckloads.
If you 're a slapper (I'm not) it also has some features to enhance the
slappiness (is that a word?) of its output. There's a guy who did a video that walks you through everything about this bass
here if you're interested.
And a video of the newer 52-5 model which is probably worth looking at if you like Cort's Curbow lineup and you're into tapping, slapping, and popping. Because the Curbow models were designed for it.
My only problem with it was the body is made out of a synthetic called Luthite. That material emits a distinct chemical odor. So whenever I first pulled it out of the case, it bothered my sinuses big time. I eventually gave it to a young kid who was starting to learn to play and was having trouble with the neck on the bass she was using. I didn't mind since I had only paid about $300 for it, and it was a worthy cause.
tl;dr - I think they're great based on my very limited experience with them.