I have had the QX10 and QX100 now for several weeks and my views on them have slightly changed. They are both excellent however I now carry the QX10 with me more than the QX100.
I carry the QX10 permanently with me as it is considerably lighter and smaller to pocket. It also has 10x optical zoom so for most situations it is a better option to carry.
If I know I will be travelling to somewhere specifically where I intend to take photos or where there might be an opportunity for good shots then I will take the QX100. The QX100 takes incredible quality photos.
But if I had to choose just one, it would be the QX10. If I wanted QX100 quality I would use a DSLR camera instead.
However, my wife and I have been out several times with our iPhone 5S’s using the QX10 and QX100 and had a great time using them. More fun actually than most cameras.