<VV> finish protection

[Christopher Ziebell]

My brother has an RV and had it professionally detailed.  They put a
coating on his rig that they called "liquid glass."  Nothing seems to stick
to it at all.  They put it on the windows, and the finish.  Even the bird
poop beaded up and rinsed off.  They say it lasts about a year and then
needs to be reapplied.

I see some products that claim to do this that market themselves as
"ceramic" or "polymer."  They appear to be more than just wax.

Do any of you recommend or use any such finish protection?  What are the
good ones, what are the bad ones?  What are the pros and cons?