I'd be very disappointed if my iPhone 4 ends up being more reliable than my iPad 2. Even though rebooting is a quick fix, I expect a lot more than what I'm seeing so far. I hope I don't regret purchasing this iPad instead of waiting for the 3rd edition.
but that is not a solution to turn wifi off and on again thats stupid.
I know this is not good too but as I said try to unchek password authetification in your router. Free Wifi and hide SSID
you will see the problem is solved