The somewhat slow maximum aperture is justifiable in keeping the lens light, small, and inexpensive.  If one needs f/2.8 or  f/1.4 speed, there are lenses to serve that purpose, usually at a much higher price, weight, and size penalty.  If one needs  reproduction ratios down to 1:1, then there are several excellent Micro-Nikkor lenses for that purpose. 

None of its peers have a faster aperture, nor, I assume, do they have better AF performance.  I have not had a chance to test the other lenses in this class, but I find it exceedingly hard to believe that they could offer better optical performance.

As a "travel lens" this could be ideal for many people.  It could very well serve all one's needs while traveling light.

Would I buy one?

I'd think about it.  I'm inclined toward faster-aperture and faster-focusing lenses.  But if I were to need one lens that could cover the widest focal length range possible, this would be my pick.  I would also not hesitate to recommend it to others.