I got my strings today and put them on. I have a lot of setup to do as they are tapered strings. My string height is way too low at this point, but I couldn't resist plugging in and trying them out.
Wow! These suckers practically play themselves. I went with a balanced set, and I can tell the difference. I'll get things set up properly tonight and give them a good test play.
The one thing I noticed is that they aren't as thick as the gauges suggest. The set I took off were Chromes with a .132 B string. The .136 Circle K is DWARFED by the Chrome B. They ship the strings in a little cardboard hanger and the Chrome B would barely fit into the hole. Very strange, but my initial impression is very favorable. I always thought I couldn't slap, but I was wrong. The Chromes didn't slap well, and I always thought it was me since I am a newbie player. But the Circle K's sound great. Just barely slap them and you're rewarded with a nice tone, and the "pop" tone is fantastic too.
As soon as I get the string height set right on my B string so I can give it a good workout without it hitting the frets, I'll let you know how it sounds. So far, it sounds really good. Very cool that you can use the same "pluck pressure" (that's the best way I can put it) to get the same volume from any string. The Chromes required a hefty pluck on the B string to get anything out of it where the D and G strings were really sensitive. The Circle K strings seem to have good even sound to them. I set the EQ on my bass flat and the strings don't seem overly bright (even thought they are new).