Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
I got the 4.3 update on my rogers s3 about a week ago and am having the same issue. My wifi signal on 4.1.2 was great. I have noticed my general reception is quite a bit better but I dont like the tradeoff overall.
Also, until I went in and turned off a bunch of crap (am not rooted atm) the battery wouldn't even last me half a day. I've fixed that but the wifi is hella annoying.