I've been using a Slick Shell bumper for over a year. The main reason for the bumper is to keep the screen raised off surfaces and still have the natural phone dimple. A few complaints: lower volume button activates sometimes with a strong press against the side of the phone (especially when placing it in my car holder), headphone jacks with lots of rubber protection don't insert all the way.

Slick Shell: http://www.amazon.com/gp/product/B00F2YEIXO

There's also one that is $6-7 on Amazon. I know, because I bought it. The $2 one from Voberry was in an expected 3 week backorder when I was case shopping.

Edit: link http://www.amazon.com/gp/aw/d/B00F2YEIXO/ref=mp_s_a_1_1?qid=1395095210&sr=8-1&pi=SY200_QL40

I didn't care much for the clear case so I bought this bumper. only 7 bucks, only one I could find that ships from the US. No amazon prime unfortunately but it shipped fast. Buttons are a bit sensitive to pushes but we'll see how it does over the next few weeks. Let me know if you need any other angles photographed.

edit: also thought i'd mention that I still feel like the moto x is best without a case, and I know motomaker warranty is awesome, but I wanted to keep it a bit more protected for when I need to sell it in a few months for the Moto X+1

I've been very happy with the Slick Shell. It's cheap too at around $7 but I've been impressed by the quality for the price.