In a vacuum, no, but considering that by getting Beltre, we'd have to put Youkilis in LF, that Adrian Beltre had a year that I doubt even he can repeat, and that we'd get 2 draft picks if Beltre signs somewhere else as opposed to giving up 1 draft pick for signing Werth, then I'd go with Werth.
If I knew that Beltre would repeat this past year for the next few years, then I'd definitely take Beltre.
Not to mention that while they are the same age, Werth is an American 31, while Beltre is a Dominican 31, so I'd be more trusting of Werth's age than Beltre's. That's probably just my small paranoia, but that can also be a tiebreaker.