we have one for my wife's VW TDI Beetle and it does decrease wind getting to the front passengers. It is easy to deploy and take down. The Beetle stores it in the top of the trunk (not the lid, the trunk itself). This storage is better behind the seat (but I wonder how it must effect the fold down of the seats? Not sure. Have to see it in person to decide but I definitely like using it on the beetle.
You're right that you can't use it with passengers in the back, of course. However, its great to put things under and not worry about the wind taking them. We used it with the seats folded down in the beetle and could therefore use the pass through from the trunk for longer things.
On a different note - my wife hates this color of leather and I really like it.
I like the contrast with the black and black seatbelts and various black seat latches to move the front seats forward or the headrest. The air scarf thing in black I like. Wife says it looks like baby poop or vomit! AGain, I'll have to see it in person.
The 4-Series windscreen was just redesigned for the 2014 models and is a major improvement over previous years. I've had three previous verts and the windscreens were quite flimsy and moved a lot when driving with the top down. They did not come with the vehicle and were an over $400 accessory. They also came in a zippered black bag with handles which could be stowed in the trunk (took up a lot of space). I haven't used mine yet, but hope it's more sturdy. Overall they do work well and extend our top down drive time on those nice Fall days. Be prepared for people to flash that "he/she must be freezing expression", however with the windscreen, heat, heated seats and the new "air-scarf" option - we will be all smiles... ENJOY THE DRIVE