I think most reviews have mentioned this exact concern (everyone knows Sony hasn't had the best phones prior to this one).
Fortunately they all seem to say that they feel very sturdy and durable. They must be in order to keep out water I guess.
my first sony ericsson phone was the t28 and i fell in love i think it was the summer of 1999 i remember it was instant i since moved on to nokia until the ericsson k850i came out and have never turned back i have had my fair share of disappointments a few angry letters but no matter what will always be a sony fan i just cant wait until they become world leaders again instead of playing catch up so its time to pull your socks up sony release the bloody handset so i can go about my business instead of constantly checking for updates on the xperia z make us proud again