Another long review on the Tamron 15-30mm. Unfortunately he compares it to only Canon mount lenses but so far so good. Looks like this lens is next on my list. Unfortunately if I get it, I won't even be able to carry any other lens.
http://dustinabbott.net/2015/02/tamron-sp-15-30mm-f2-8-di-vc-usd-review/
Pros:
Excellent wide open sharpness that only improves when stopped down
Effective image stabilizer (VC), the first of its kind in a wide aperture, wide angle lens
Fast and accurate focus via USD drive
Excellent color rendition and accuracy
Great focal length and a wide aperture
Exceptional contrast
Robust build with weather sealing and fluorine coating to prevent water buildup
Low distortion
Vignetting and chromatic aberrations well controlled
Highly flare resistant
Very attractive sunburst
Nice softness in the bokeh region
Very reasonable price – a bargain compared to the performance
Great six year warranty
Cons:
Large and heavy (largest and heaviest in its class)
Traditional screw on filters cannot be used
Early indications are that supply will not equal demand upon release like the 150-600 VC last year.
No case of any kind provided
HIs sample photos: