About 2 months ago I bought a new Canon 5D Mark II, one of the best FF cameras out there. I mainly shot stock, textures most of the time, but also details, landscapes and so on. I needed a lens that would help me in every situation.
That's it: Canon 24-105 L.
Well, L-series lenses are Canon's models of excellence, top quality lenses provided with top quality construction body.
First thing first, the body. It is made in sturdy magnesium alloy, it's waterproof, and the focus and focal rings run so smooth it's a pleasure tu use them. I have to say that my models has a little hard focal ring: it isn't a flaw anyway. This lens weights 670 g, resulting a little heavy to carry.
Speaking of quality, this lens performs really well, although you might notice a quality decay in the corners and a bit of vignetting at 24 mm, other than a pretty visible barrel distortion. These flaws vanish at higher focals, but I find them to be relevant while reviewing a lens this important. We're talking of a L series lens afterall.
Brightness is good in the whole focal range, F/4 is bright enough to let you shot in low light condition. At F/4 and 105 mm it delivers outstanding bokehs.
The most important thing about this lens is the image Stabilizer: it really helps you getting clear images at long exposures. For example, you can get a sharp image shooting at 60 mm and 1/30 s.
This is a very sharp lens at every focals, delivering the best quality stopped down at F/8, like every other lens in the world =)
The only complain I have to do is about the flaws I talked about earlier: vignetting, barrel distortion, sharpness decay in the corners.
Nothing that bad though, they are easily correctable with photoshop or any other professional software. It just sucks, that' all.
To summarize: greatl lens, great focal range and big quality.
IS helps you a lot. If you have a FF camera, this is THE LENS for your general purpose shooting sessions.
I'd rate it 9 OUT OF 10.
Hope you find it useful, here are some samples =)