I used Meguiars nxt tech wax on my XF last fall. It worked really well and was easy to put on, for sure. The first thing I tried on my car was the Crystal Guard everyone was talking about on the forum right after I found it. It was pretty expensive, very easy to put on(you just spray it on the wet car before you dry it off), but it didn't leave it with that slippery surface you get after waxing. It DID bead up really well, so it must have been working, but I didn't slide off the fender when I leaned on it. The Meguiars did a better job of doing that. Then I saw a picture of Buckeyedad42's black car and it looked like a mirror. He said he used Liquid Glass on it. I bought some of that product but it hasn't been nice enough here outdoors for me to try it on the car. My car is the white alabaster, and I don't think it looks as the metal flaked colors can. The Liquid Glass claims to offer a life-time protection after 2 coats so I'm thinking it probably does a good job of actually protecting the paint, not just making it shiny.
Hoping for some nice weather(It snowed here about a foot this past weekend) so I can go out and try it. If you already bought the Meguiars nxt tech wax, I would use it. Harry 7 is right about it not staining the rubber parts. That's a BIG plus!