I have been testing CSL for a while now, with our longest test panel approaching 6 months of abuse. The panel has been washed just twice in the 6 months (most recently last week), and the coating is still as hydrophobic as it was on day 1. Pretty impressive given the circumstances.
I also have CSL applied to the hood of my personal vehicle which is maintained to the highest level and it is performing perfectly, as expected.
To be perfectly honest, CSL is our favorite consumer grade coating on the market right now. The slickness is off the chart, application is a breeze once you get the hang of it, and the protection seems to be on par with any other coating out there.
As far as the 5 year durability, you will notice that GTechniq does mention that in order to maintain hydrophobic properties for such a duration, the coating may need to be topped either with a spray sealant like C2 or with another coating like EXO. However, as we know, water beading is not a representation of actual protection... without opening a can of worms, I'll just say that most vehicles can benefit from a light polish every 1-3 years depending on how they are used, therefore I personally don't pay much attention to coating durability claims past the 3 year mark.
I would highly recommend checking out CSL if you're looking for a new coating to try... you can find my "Initial Impressions" article on the DI Ask-A-Pro Blog.