I bought two sets of these for outdoor lighting on my patio.  The set stuck to my painted metal railing work great--no complaints.

The set stuck to painted wood?  Absolutely nightmarish.  This is the third day I've had to replace strips  as they keep falling off--and they're holding the lightest set of lights!  I'm almost to the point of tearing them all down and going with finishing nails--which completely invalidates the entire point of buying these.  Please keep that in mind if you use this product.