At least here in Sweden, while VFR on top is allowed, and VFR at night is allowed (with an NQ), VFR on top at night is not allowed. Not sure what to make of that, or if that's a local thing...
Various well defined weather planning minima also apply, including forecasts of no more than 4/8 cloud at the destination at the planned landing time. A rather peculiar national regulation is that it is illegal to depart cross country without weather forecast printouts onboard, if forecast weather is below 8 km visibility and 2,000 ft cloud base (not ceiling!) along the planned route...
On the other hand, if the forecasts show that the cloud cover and layering is such that VFR on top is allowed (and planned), the normal legal planning minima of 1,000 ft ceiling and 5 km visibility along the entire route are relaxed to only apply to the destination area.
So a lot of hoops to jump through to legally go cross country when WX is less than perfect... As it should be, IMHO.
In those situations when it is allowed, VFR on top seems like a sensible thing to me! I'd be a lot happier at FL085 above the clouds, than at 800 ft AGL below them...
