[Russic]

Depends on a few factors. How often will you be hand-holding the camera instead of using a tripod? Is there an instance where you'll be shooting in lower light more often than not?

For somebody using it to take pictures while they go hiking it may not be as useful as somebody who's buying it to take pictures (edit: poor example) without a tripod in low light.

Personally I went with it just because I wanted the lens to be as versatile as possible. I stand by my decision. It doesn't make a night and day difference in my pictures, but it certainly has saved a couple pictures from being throw-aways.