I have this case on my SP4. I got it since I travel often and I need to use my computer out in the field. It is a nice case that seems to provide good protection. I have not dropped my SP4, so I can't verify well it will protect my SP4.
I compared this to the Urban Armor (UA) case, and I decided on this one because it had a built in pen hold in the back of the case that seems more secure then the UA. Its a fabric loop that looks like the one Microsoft sells at the store verses the clip style on the UA. It is located in the back of the case and the pen is almost flush with the case.
Since you asked about the kickstand, I think this kickstand is better than the one on the UA as it is more like the SP4's kickstand. It also has to 2 rubber feet on the kickstand. I find it to be more stable when I am working on my lap. What I improved on the kickstand is I to add a third notch on the bottom center of the case to extract the kickstand. It only has notches on the left and right to put your finger in to open the kickstand. The Dux range of motion for the kickstand is about the same as the SP4.
With regards to thinness and lightness, it adds a lot of heft to the SP4 and the thick rubber corners adds girth. The extra thickness allows for the pen to be stored in the back of the case. So could be a deal breaker for you.
Putting the case on and taking it off is easy. It works well with the Typecase. Speaking of the Typecover, mine is bright blue, but the Dux is black, so that looks kind of funny. However I just saw Amazon is selling a blue version of the Dux that matches the color of my Typecase.
Note, the SD card slot is blocked and not accessible when the case is on.
Hope this helps.