He's the next Bruce Smith for the Bills. I think this is actually a really big step for them. As a signing, maybe their Reggie White.
The extension of Fitzpatrick doesn't look as good as it did those first few weeks of last year, and I'm unconcvinced he's their next Jim Kelly...but in any case, this is something for the Bills to be excited about.
As for Ware and Allen, if I'm not mistaken, Ware signed a 7 year deal in 2009 and Allen still has a couple years on his contract, right? We can debate their merits vs. Williams, but they are simply not available this offseason.