My favorite case is the Magpul. Best case for the money and it still provides the protection I want. I tried other rugged cases; Tech 21 Patriot, Otterbox Defender, Griffin, etc and found that they take away from the iPhone 6 thinness and appeal. What I liked about the rugged cases is that they came with holsters. Since I have been rocking the Magpul I've been carrying it in my work jacket breast pocket which works out OK. I work outside in a construction type job and really don't like carrying it in my work jacket breast pocket. I'd rather have a holster type case for my Magpul. I looked at SF Bags Spinn Case.... But since I bend down a lot at work it looks like it might get in the way of me bending. http://www.sfbags.com/products/iphone-spinn-case In the video the guy says it can turn when you sit but I bend multiple times a day. Can anyone comment on the Spinn Case?
I have it and I like it. Bending down can be an issue, but it slide back and forth easily on the belt and I do this almost unconsciously. I find it gives me more range of motion with the phone by my side then in my pocket.
I'm not familiar with the Magpul field case, but my iPhone 6+ with the leather case fits - its a very snug fit. If the Magpul is any thicker then Apple's leather case, then the answer is no.