Don't use an Apple hand-held device. They suck when it comes to roaming and hand-offs and will hang onto a network that has become useless WRT signal strength and throughput, even if a stronger one with the same SSID is closer. This isn't restricted to hand-helds, either- I have seen it with iMacs, several times.
My mechanic told me, "I couldn't repair your brakes, so I made your horn louder."
