no free google navigation until HTC updates Sense to work on 2.0 which could be anywhere from weeks to months from now, but rest assured it is coming.
the biggest differences b/t the moto and the eris are the hardware specs underneath. the droid is a beast with a blazing processor, seperate graphics processor, more RAM, bigger higher res screen, dual LED flash camera, and the physical keyboard.
the eris is older specs, but at a cheaper price, and is a more traditional design that weighs less and is thinner, and of course running the pretty SenseUI