Personally I'd go with whichever gives better performance out of the box. I'm not a big fan of OCing anything, but that's just personal preference. I figure if it isn't good enough on its own merits, why get it? I realize that for some folks, overclocking is just standard operating procedure; but I want my components to last, avoid voiding any warranties, avoid the need for fancy or excessive heat removal components and prevent any instability issues. It may cost me a little more to buy something more current rather than OCing an older component to get the same or slightly better performance, but that's just me.
JMO, pick whichever goes faster out of the box.