As much as I like the Ascend P6, I'm gonna have to vote LG G2 Mini based on paper specs. The G2 is newer as well. If 3D graphics processing is important to you then definitely go for the LG G2 Mini.
I'm not sure if we have them here yet, but the Huawei Ascend P6S would get my vote over the G2 Mini.
One thing though. Unlike the G2 Mini, the P6 doesn't have a user replaceable battery.