As the others have said, go with a digital scanner, GRE/Uniden doesn't really matter. The best one is which ever your friend finds that works best for them. Ether way, I'd also recommend getting one of the many programming software packages out there, it not only decreases the learning curve, but also can allow for recording, streaming over the internet, etc. As for files, I've got a file for Oakland County using a GRE PSR500 programmed with WIN500.
