Had the exact same issue, it was driving me nuts. Retina MacBook Pro 2012 would not connect to an Airport Extreme base station. WiFi would appear like it's working for a moment, then get the exclamation mark, then I had to turn it off and on again to make it work; sometimes it would also just lose it during operation and I'd have to turn WiFi on and off. Never had issues before Mavericks.
Tinkered with all sorts of settings on the WiFi to no avail.
The PRAM reset seems to have fixed it but since I tried so many things it's not clear that this was the only thing I needed to do. Here's what I did:
- Create a new location in Network Settings
- Turn off Bluetooth
- Reset PRAM two times in a row
Laptop seems to connect to WiFi fine now. Should I have issues I'll turn off iCloud Keychain. Turned it off on the iPad too, and that fixed things there. The iPad had been very unreliable and slow on WiFi before. Will turn it off on the phone too.
iCloud Keychain is new in Mavericks so that's a red flag - might very well be what's causing this.
My theory on why this happens much more at home than anywhere else is that I have two iPads with iOS 7, two iPhones with iOS 7, and one laptop. Now I think if the WiFi is flakey on all of these thanks to keychain, there might be a compound effect where IP addresses "are already in use" - it confuses the router and makes things worse for all devices. Just a guess.