[Klaus]

To put things a little into proportion:

 

Nikon 17-55/2.8: 30% more than the Fujinon

Canon 17-55/2.8: 33% less than the Fujinon

Pentax 16-50/2.8 DA: 4% more than the Fujinon 

 

bean-counting: None of them covers the same FL-range and 1 mm shorter does make a difference at 17 mm

 

Did you check out the verdicts from Photozone? The Canon being the big exception, but the other two are not shining so much more.

 

Sigma, Tokina and Tamron all have some major differences: The turning focus-ring. It's obvious, therefore they can be cheap, but it's also obvious, they are not worse than the Fujinon. And none of them is weather resisting for those who care.

 

Nikkor: 85.5x110.5mm • Weight: 755g

Fuji: 83.5x110.6mm • Weight: 645g

Canon : 83.3x106mm • Weight: 655g

Pentax: 84x98.5mm • Weight: 565g

 

The Pentax is actually the most compact and light-weight of the bunch.

Not sure what you want to tell us with those % figures.