I've not tried McKee's Coating, but have tried both DP and Pinnacle Diamond Spray Coatings when they first hit the market, and have to be honest, I was not impressed at all with either of them.
I did my Kia Spectra Daily Driver junkmobile with the DP, and that was after a full polish and wipe down with Eraser, and noted the ease in which wash induced marring-swirling occurred. And I used both on other little projects, such as my Cargo Trailer's Fenders, and neither lasted. Sitting in blazing sun everyday, those fenders again re-oxidized within just a couple-few weeks. I actually found Colly 845 to protect longer.
YMMV, but that was my findings with those two products. The science may be different, but those products, unlike some others, will not turn an applicator hard as a rock like the Carpro Products will, and I'm sure some others, from Optimum, and probably GTechniq, and perhaps Gyeon, etc
As for products like McKee's, or the DP, or Pinnacle, yes, they are relatively easy to apply. As long as you're not trying to apply these sprays in gale force winds. Because 1/2 the product you are applying will be wasted.
Slickness of feel, yes, the DP, and Pinnacle Coatings were some of the most "slickest" products I've ever used bar none. If all the proper prep is done beforehand like claying, and polishing, the final buffing towel will not stay on the vehicle, that slick.
In the McKee's nomenclature of this coating, it goes on to say easy, etc etc, but as all know here due to common sense, and the description of use touches upon such, you cannot throw these coatings upon a paint that might have other waxes or sealants still on them. You have to start with a clean slate, meaning squeaky clean paint, hence the paint prep is mentioned which will remove other products beforehand.
With improper prep, no coating will properly bond and protect as advertised.
On sale right now for $27.99 plus 20% off. Can't beat that.
