I notice it most for big compound movements. I cycle on and off of it. And when I go back on I can tell the difference and all the scientific studies back up that it works.
I run a push pull legs program. Biggest thing I notice is the "pump". It's far easier to get a nice pump going when I have creatine in my system vs not. This definitely aids in forming a mind-muscle connection, and at least in my personal experience a good pump is an indicator you're training properly. Around this time last year I was having trouble finding any, and the difference in my performance was night and day as far as being able to reach progressive overload.