Hii,
the build quality is so good quality its waterproof mobile. this mobile is good features. it is the one of the first phone of song with so many features this phone have designed by really special people which work for sony.
you will get a 3 gb of ram and a 32 gb of internal memory. you can also expend the storage till 256 gb via micro sd card.
its front camera quality is also good one.
thank you