I prefer Sony smartphones over Samsung because of its good build quality and attractive slick looks. The problem with Sony phones is there poor software support means just for example there ICS upgrade program is horrible the ICS Roms are still quite buggy and there 2011 xperias ICS upgrade is not usable by any mean for daily normal use like broken Wi-Fi, Tethering problems, lagy GUI, restarting, camera video lag and the list goes on..... But if we are not bothered about upgrading OS of the phone and can enjoy the smooth fluid stock ROM then Sony is the best choice .
I'm totally prefer Samsung phones over Sony phones just like the mass.
I've played with last year's Sony flagship, it sucks. The UI is not fluid, the icons are very small. It feels like windows xp comparing to SGS3's windows 7. lol.
also, phone design and build quality doesn't mean anything when you get a case/bumper to cover up everything. Everyone I know of uses $1 to $20 cases to protect their smart phones. It's funny my iPhone 4S friend says he prefers his glass back over my SGS3's plastic back. I'm like, yep, the plastic/rubber feeling of your phone's back cover is "better" than my plastic/rubber back cover