Adafruit has one they are pretty high on. Has a PPS (pulse per second) output once it has a fix, fix status led on board, battery backed up RTC capabilities, some build in datalogging capability, and a means to automatically disconnect the on board patch antenna and connect an external antenna/preamp via a connector.
They claim it can track up to 22 sats on 66 channels and a 10Hz update rate. I don't think they get much better then that?