Four different Z5 handsets in one month

I am so disappointed in the Z5! I upgraded on 01/12/2015, totally excited as I had just decided to stick with one brand of handset as I had the Z1 before & my brother the Z3. All four handsets I have had to return & finally chose a Samsung S6 yesterday. I have never been so disappointed I in a product. The handsets each had different faults except for the one common fault which was verified by a Sony representative.