When it comes to slim and light weight cases, Spigen never disappoints with their unique and rich styles. But in the past they weren't exactly known for their rugged touch. With their Slim Armor case it looks like they decide to turn the table around. So let's see if they were able to add extra "armor" protection while still maintaining their typical slim design.
Slim Armor is actually consists of two layers. Inner TPU layer surrounds the phone with extra cushion to absorb shock impact and adds extra thickness at the top/bottom bumper beyond the boundaries of Outer PC layer which bounds the sides and the back of the case with hard plastic material. Still, even with two separate layer, case feels very thin. The fitment of both layers is seamless and almost feels like one piece. Every port opening is precisely cutout and perfectly aligned between inner/outer layers and with a phone. What I found especially amazing is that case is actually easier to fit in with a phone while two layers are together. This was a pleasant surprise since I know that a lot of people like to take their cases on and off and when you are dealing with two layers it becomes a hassle to constant align two together. For the purpose of pictures, I demonstrated how the phone looks with inner layer without outer shell, but in everyday use I would recommend keeping both of them together when taking phone out.
One of the details that keeps both interlocked perfectly together are the power and volume buttons. Those are part of TPU inner layer, but made to feel and to perform like hardware buttons. A separate cutout around sides of these buttons makes them very easy to push with a nice tactile feedback, and while aligned with outer PC shell cutout it keeps both layers together. There is not too much to complain about Slim Armor except for the lip around the display. Typically those are designed to keep your phone off the surface when faced down. To my personal taste I found this lip to be very shallow. Actually, it's more shallow around the side edges while a bit more thicker around top/bottom part of the case's bumper cushion. So in theory it will protect your phone screen down from touching a surface, but you will not get as much clearance thus I highly recommend having a decent screen protector when you use this case. For those familiar with Spigen, you know that quality screen protectors is one of their signature products. Another thing to mention, which was actually a pleasant surprise, is a bonus of 3 home button stickers labeled as "jelly bean" buttons. Those come in assortment of 3 colors and will help you personalize your phone even further. The case itself comes in a selection of 5 different colors for the hard outer shell. The one I got was in black, and somewhat a fingerprint magnet. For those who are bothered by this, probably a good idea to go with a lighter color PC shell
Overall, this is a very impressive and high quality case (made in Korea, which I find lately to be of a higher quality than HK built cases). You will still get a slim and light weight design while maintaining a piece of mind in case if you drop your phone. Even so I wish the lip would be thicker to offer a better "armor", bundled with a good screen protector you should be OK.
Here are the pictures of black Slim Armor case I tested with my S4 display model of the phone (thus a slight misalignment of mic port next to micro-usb connector):