I found they reduce condensation overnight. We still get some but then we have internal thermal window covers and I believe that condensation is one of the pay offs with those (with external covers reducing this?). I tend to leave the top suckers off the glass so there is a gap for air to circulate into the van - this helps a lot. If I forget or if the gap between thermal cover and window gets closer then we do see more condensation.
As for blind spots people are talking about I have the light smoke Climair and these are fine to see through. Not a dark tint like some others and the shape is one smooth curve - some (maybe Heko) seem to have more of a distinct fold/crease in them and that will obscure vision when looking through them.
