Just spoke to Samsung support about my 6 wk. old G4 with continued WiFi problems.
After jumping thu the hoops of waiting on "hold", then popping the battery and giving them the appropriate serial numbers, I talked to a rep. who talked me thru various things that I already tried, then transfered me to level II support to someone I spoke to for 15-20' and re-described the problems I've been having with WiFi (which have worsened lately). Essentially, he couldn't do anything for me and told me it was up to ATT to replace the device.
CONCLUSIONS: Samsung has a real (software or other) problem with this phone, Samsung's customer service leaves much to be desired, and I want my iPhone back!