Telephone is always a matter of personal preference and feelings.
I was not meant to say that the x10 is better in any field compared to x1.
When you get used to it I do not find any big difference in usage, but this is a matter of taste or habitude.
I found, so far,the x10 more stable than the X1; it is also true that I have not many applications installed but I use it as I did use before the X1.
Display of the X1 is better and this is way I consider the x1 better for video and films. Also going to internet having a bigger display is better.
Camera on x1 has more options.
Price is also a decison factor, but I believe that if you go with X10 mini is because you want to go with Android. And, besides the cooked roms, the difference between WM 6.1 and Android is abysmal.