I picked up one of these MOFI kangeroo cases as well, but gave up on it after a day of use.
The inside lining does clean the screen most of the time, but the rest of the case is the issue. The cloth exterior is extremely...well, grippy, meaning when you try to pull out the case in your jeans pocket, the pocket lining gets dragged out with the case. Its also too furry for me, because the last thing I want is to be sweating all over my case when summer hits in a month's time.
I'd say that this case is great for those who keep their phone in a briefcase/handbag/backpack etc, but the useability drops significantly if you are the type to put it in the front pocket of your jeans.