As of today (17th July) CyanogenMod 11 is only available in a semi-functional version. With both GPS and the camera not working it could not be considered a daily driver, and of course there are plenty of other minor niggles.
Samsung has introduced lots of great features in its latest version of TouchWiz, and I have always liked the swipe left and right on contacts to send a message or initiate a phone call since it was on the original Galaxy S, but this single likeable feature is does not compare to stock Android.
The cleaner look, the instant responsiveness and now with Android L the promise of better battery life we all know that TouchWiz cannot compete.
So far I have turned off most of Samsung's proprietary functionality, and found the finger print scanner and heart rate monitor to be next to useless.
The Galaxy S5 is still the best phone I have ever owned, but a Google Play edition or CyanogenMod would be a massive step up in usability, speed and enjoyment.