I have wondered the same thing. The Internet shows up as an active app even though I close all apps by going back. This has nothing to do with Wi-Fi.
I agree with Dave-in-Decatur. Don't paint the S4 with such a broad brush. I have had the S4 since May, and have had no WiFi problems either before or after the latest system upgrade.
Kit Kat is probably coming soon. Sprint users are getting it now.
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