Well, the nice thing about the 1300's is that you could use an EQ on them, whether that is through the Razer software, I'm personally not a huge fan of but others don't seem to mind it, or an EQ of a soundcard should you decide to buy one.
It seems like the Plantronics sound good as it is, but the lack of an EQ would push me away. If that doesn't bother you or you don't want to deal with using a software EQ, then I would probably go for the Plantronics.