Streetdeck is not currently available with European maps. You can buy the lite version and use european mappoint maps, but there are some small drawbacks. Also note that on a cross-country trip a couple months ago, there were some periodic issues with the navigation. Hopefully they've got those fixed by now or in the near future. It's definitely still under development, but I think it's only going to get a lot better and it's being consistently improved. I'm anxious to see the new music interface in the latest version. I wasn't too keen on the old one after being spoiled with the empeg.

EDIT: I just loaded the latest update and the music selection interface is much improved. It's not quite the empeg yet, but it's getting much better.