I've had my Laminar Lip on since early 2010. I use it on the stock screen and a cut-down GIVI screen. It has never come off without some tugging, and has been to 105 mph indicated. On the Silverwing, I use the hook-and-loop fasteners and have removed it at least a dozen times without problems.
I find it makes the airflow much quieter than the stock or GIVI. Well worth the money to me.
I also use one on my windscreen on my Vespa GTS. Also very effective.