Received my MvG over the weekend (for a 276c). Have just tried it out on the run in to work.
It's a tough call on whether it's worth the money or not, strictly speaking I'd say the extra components required would likely cost the 35 euros extra so it's worth the money from that perspective but as to whether the MvG is worthwhile overall, I'm not yet sure.
I used to have a regular TT mount for my III+ and that served me well for a good 40,000 miles so when I upgraded I thought I'd get the new fangled MvG design.
I have to say it freaked me out when I installed it on the cross bar, there's a good 20mm of play in the cradle, (it moves so much I thought it was duff and so checked with TT to make sure it was right). TT were great and re-assured me that this was normal and as a result of the design and the free play, the cradle is effectively physically seperated from the cross bar. I checked it out and although the cradle does move, any movement is now subjected to appropriate damping to ensure that the GPS receives no violent movement.
It's kind of the nodding dog theory rather than the violent shaking at low revs but solid at speed theory.
I guess TT's thinking was that damped vibrations all the time are better than sharp vibrations some of the time.
Time will tell I guess, I'll let you know anyhow
Dave