I’ve been playing with the module over the weekend and so far, I’m impressed with its sensitivity. I’ve gotten a lock inside my house within 38 seconds from a cold start and I’ve been able to track up to 11 satellites. The antenna I am using is an active Sarantel.
I’m pretty sure the only way to communicate with it is through the async port and the SPI port is strictly for data logging to an eeprom chip.