I use the Etronix Pulse, it's exactly the same as the Core RC and it's £10 cheaper.
Had a problem with the first one I got but got it replaced and it hasn't missed a beat so far. Sticks are a bit long but nothing that a Dremel couldn't fix.
I'd be less disappointed dropping the Etronix than say an Esprit 3.
Is the KO better? Yes.
Does the KO have a faster responce time? Yes.
Am I good enough to tell the difference? No.
Would I rather have £300 in my pocket? Hell yes.