It's rather the otherway round. In a year's time Samsung drives go kaput. Most of them either develop a tray problem or some problem with lenses. The shopkeeper is misguiding you cos he maybe getting better profits on Samsung drives.
I haven't used a Sony drive but have heard good things about it. As for Samsung, I have personally experienced the horror of Samsung drives. If you don't believe me just make a search on this forum and you will gets long stories of tragadies of people who bought Samsung drives.