Xperia Ray or Xperia U

To hyper-jump into 4 generations of Android from S40 Operating System, is about transporting into human time by 35 years to 42 years (calculated in dog years).

So I have zoomed down to two:

Sony Xperia Ray
Sony Xperia U

The only shortcoming of XperiaU is no microsd slot, it has a dual core system on board. SOC.

So suggestions are welcome. Comments please.