I have a previous version of the James Cook, sold in the US for a short while under the Airstream label. Not quite as lavish as the current version, but every bit as thoughtful and useful. At only 18 feet long, she's nimble, and fuel efficient. The three of us use ours all the time, as once you get used to always having your own kitchen and bathroom wherever you go, well, it's hard to drive anything else. We've spent two weeks on the road at a time, and could easily go longer, but that's the most time off I get at a time...
We take it skiing in the winter; my wife escapes the lodge mob scene, and my kid can take a nap while I get some afternoon runs in, while they bask in the warmth of the diesel-fired space heater. When I come back, there's hot chocolate on the stove, waiting.
Westfalia really makes a nice product. You can tell major assemblies were jigged and cut on CAMs; joints are tight, and fit and finish are above most American products. Westfalia is not an outfit housed in a warehouse. They're more akin to a vehicle manufacturer, with actual engineering and R&D departments. I can't explain it in words, I guess, but you know when you look beneath the skin of a Westfalia, that more than a few people had a hand in refining the design. A look at the Westfalia lineup in Europe will confirm my impression.
I could go on and on, but the fact is, if you've considered a Sprinter for a camper, there is no layout that will beat a Westy Sprinter. The high top makes it all possible, by providing room for a REAL, no-kidding, bed. No seat cushions rearranged. Heck, it's even got a box spring system under it! It's really comfortable, and that makes a huge difference in a campervan, where every other kind of bed is a compromise. With the Westy, you can even leave the bed unfolded, and made up; it's sufficiently over your head to where you just duck a little...
Here's a page from a dealer in NJ with lots of pics...
http://www.colonialairstream.com/preowned-rvs/c084.html
Here's a pic of mine, heading out to Acadia NP for 10 days...