The 3S is also available with band 20.
I've got the RN3 SE. Build is as good as my Xperia Z2. Miui 8 is better than I expected, but it's memory management is poor. I don't know if Cyanogenmod/Linage can solve this.
It's a lot of phone for the money, but bear in mind coming from China, any warranty is virtually non existant.