There has been a lot of slim cases like the Rearth Ringke slim, spigen and others. The amCASE ultra slim is a bit different than the others.
First, its thin alright. Fits well and not much wiggle room when in the case. The back has a nice soft matte grip finish, No corner was sharp but a nice smooth rounding on all sides/corners. There is some lift ont he bezel around the phone so it lifts the phone just a bit to prevent scraching the glass on the front when setting it face down on a table.
The amCase differes in that there is no bezel by the buttons on the phone. While it makes it have even less protection than other slim cases; it makes it a lot easier to take it off and on. The Rearth slim I have has just a good fit but the buttons would always get caught when taking it off or on.
It doesn't add much protection on the bottom or sides which is nice to have complete free access to all the ports/seakers.
This is definitely not a case if you're clumsy with your phone but there to prevent the small drops or scratches. Very minimalistic and good construction witht he added bonus of the easiest to take on and off of the phone than other slim cases