USPKS helped address a lot of the issues that karters had with WKA at the time. More track time, time certain schedule, live practice timing, more racing, fewer classes and the racers noticed. WKA followed suit and overhauled their format to make it more racer friendly.
I was at the WKA and USPKS races at Mooresville the last two weekends and I think both series are doing a great job for the racer. I can only hope that the competition between series will only help improve the series for the racer.