I had used Xperia Z n XZU ( 3g n LTE) n my only complain is its very weak phone speakers ( due to extra membrane on speakers for waterproofing). Had several bad experiences missing call in noisy environment. I discouraged those to buy if they wish to use as media entertaintment unless they don't mind using a headset or earphone with it.

Is that original from Sony or OEM w Sony branding?
Never knew Sony now sell the cable alone.

Why debate over OEM UI or Vanilla android?
Both has its pro n con
I won't even want to say which is better. Just suit yourself to what you need
It doesn't make you smarter or dumber if you had chose either the built in UI or vanilla UI
Personally I had never like all the manufacturer UI but I don't say is not good or poorer. It depends on final user needs

My only Sony experiences was Xperia Z n Z Ultra ( both 3g n LTE ) and must say most impressed with its stamina mode. I would say is only phone that really works on its battery saving by default without need to use any 3rd party apps or need to disable any stuffs. On standby with wifi n 3g/lte on the battery left hardly drops. Overnight over 7-8 hours the most I had seen was merely 1%..I believe this software tweak has since been in Z2 n Z3 too.

Just hope they don't decide to close/sell off the mobile division as in Vaio notebook range
I still see Vaio being sold at Sony outlets. Who is covering the warranty now?