I applied Opti-Coat 2.0 to my car about 2 weeks ago. I am far from a professional detailer, but after washing/claying/polishing and finally opti-coating, it looked pretty darn good. I did have a little trouble achieving an even application of the opti-coat and I may still need to correct a few spots, but otherwise I was quite happy with the results.
Fast forward to my first wash of the car since then today...and WOW. This stuff vigorously repels water and presumably just about everything else. It definitely seemed to stay cleaner longer. I don't think my soap and wash mitt were even needed to get this thing spotless, just a quick rinse had it looking very nice.
(Above photo is from a couple days ago, pre-wash, but I figured I had to post something)
I still need to apply it to my wheels and see how much it helps with the brake dust, so hopefully I will get to that soon.
Final verdict: I can't recommend this stuff enough, it is awesome.