It's really a Coke vs. Pepsi argument if you do not provide details about location or what you want to listen to. There is no correct , single answer to, "What is the best police digital scanner?".
It depends on many things, not limited to, antenna, location, base or mobile, simulcast, and MANY other factors.
My advice is do some leg work yourself and read the forum for your area, Uniden, and Whistler, then make an informed purchase.
Draf