I THINK they're the same unit. It's just that the "base" model comes with the latest map revision ... and no more. When the maps are revised ( updated ) you'd be notified that a revision is available but you'd need to buy the revision to download and install it in your unit. The alternative, "with lifetime maps" purchase costs a little more, but subsequent updates are provided at no further charge for the unit's "lifetime" (or for yours). I think the latter was a better buy and so that's what I chose.
The "maps" feature can be updated regularly by hooking it up to a computer and downloading the new map information. It appears that the memory inside the GPS does not have enough storage capacity for all of the map updates. At least that is what this person is saying was his/her experience. I haven't tried to update any maps yet, so I can't verify the Garmin's storage capacity. I can't imagine that it wouldn't have enough for at least one or two updates, but I have no personal knowledge.
There is an option to change the keyboard to German. There is no German voice preloaded (that I could find), but you can download additional spoken languages for free using the PC software that comes with the device.