I went through this a few months ago. I've never seen the Kobalt, but I went with Gladiator rails and Craftsman accessories. The Craftsman accessories are comparable in price to the Gladiator...but they lock. This is huge. I know about half the time I'm taking down a shovel or my trimmer, it hangs up on the hook. Without the locking version, I'm 100% sure I'd be pulling the hooks off the rail. That would frustrate me to no end.
The little locking knob that you give a quarter turn on the Craftsman makes all the difference in the world. If you go to Sears, they carry both. Try them out on the display and you'll see the difference.