Just fitted our Calitop today. Arrived quickly from Dierk Schroder in Kiel. Love the fact that it has separate panels (we got four), and that you can use the side panels inside or outside the bellows (and leave them on if you fit inside). It was a little scary marine-sealant gluing the hooks and bits onto the rising roof of our three-month-old Beach, but they seem unobtrusive when on.
Dierk only has instructions in German, but we managed to get a German friend to help us work things out. I can share that if anyone else ends up in the same position!
None of these toppers are cheap. There's a slightly diy-feel to the Calitop - not the panels, but the various bits and pieces it comes with. I think our only real problem, though, was with some of the elasticated loops which have been fashioned into loops using a cut-off cable tie. One of these snapped on first fitting. To be honest, though, once you see how it's supposed to work, you can easily find something a little better for these.
It hasn't yet been tested in rain or wind, so we'll report back. Meanwhile, it's light and easy to stow and a doddle to fit the panels.