Yes, I would recommend this to a friend

Consistent Output; Durable; Fast / accurate auto-focus; Rugged; Strong Construction

Poor in Low Light

For starters, anybody who expects stellar optical performance from a 11,1 zoom, better stop reading right now. It is not going to happen, not with this one, nor with the Nikkor. I got this lens in a hurry, because I needed an all-purpose lens to cover a spur-of-the-moment client event.

? Solid build quality & finish; surprisingly good focus speed and accuracy; ? Overall pretty decent optical performance; except at the very long end (in my sample); ? Pretty unobtrusive internal focus; no rotating front-end.

? Chromatic aberration and purple fringing on highlight edges throughout the focal range, especially wide open; This can, however, be easily corrected in post or even in-camera (select Nikon models), ? Pronounced barrel distortions at the wide end, some pin cushion in the medium to long focal...

Epinions doesn't allow embedded photos, which is a shame for camera/lens reviews where the photo is

Small, compact; Good optics for such a wide range

Soft corners at 18mm wide open; Canon version must be focused parfocally above 135mm

Great lens for weddings and group events. I also use a Nikon 80-400 VR, so with this new Sigma 17-70mm OS I can cover most situations.

Consistent Output; Durable; Easily Interchangeable; Fast / accurate auto-focus; Lens lock 2 prevent creep; Multi-purpose; Nice Bokeh; Rugged; Strong Construction

A great lens which has taken so many good photos for me, I would certainly recommend this lens

cheaper than official Canon; sturdy; reliable; great zoom range; fairly good focusing; great picture

lens creep; a bit heavy; could possibly be built with better f stop

Great lens, focus and aim is great. A little noisy at times & doesn't perform well in the heat struggles to focus a bit but nothing a little flick off of the power button can't handle. Good quality well made and has taken some amazing pictures at close and long range

I bought this lens after a massive amount of research, I wanted to find a lens that compromised of two possible lens into one big lens so it would be easier to carry around. I also was feeling very limited by the current lens I had which was Canon 18-55mm basic kit lens.

Cheap; good build; good quality photos; large focal range; no front element rotation

A bit soft at 200mm

I spent a lot of time comparing this lens with others as a potential replacement for the Nikon 18-55 kit lens and the Tamron 18-200mm I had been using as a Hiking Lens. I gave the Tamron away and decided on the Sigma following detailed study of DPreview.com great lens sharpness and performance...

I have had this lens on my XTI for about 4 months. I am not sure about all the photo terminology, but I can tell you the following: If you are taking shots of people, MAKE SURE YOU HAVE A LOT OF LIGHT. Otherwise, the picture will not be sharp.

Zoom range

Difficult to obtain SHARP shots

SIGMA PRODUCTS TEND TO A QUALITY OF EXCELLENCE, FOR IT IS SO EASY AND SAFE WORKING WITH YOUR PRODUCT WHATSOEVER SEGMENT, SUCH AS LENSES FLASHES ETC.