Just to chime in. We just received a batch of 2 Vostro 3360's today for employees and neither machine can connect to Wifi reliably. The first time I connected it worked ok, but after a reboot it will not connect again. It seems to be a driver issue indefinitely because both machines are behaving identically.
I work in IT for the company so I run into advanced networking issues all the time, but this one is definitely faulty drivers or hardware. Curious if Dell knows this is happening in some of their Vostro class machines.