I used to own it with my 5D. loved to use it for reception. great range. sold it, then sold the 24-70L, then sold the 16-35L, now I mainly use the M8 + 28 and 50.
I just tried one out today lonaed out from my local brick and mortar(go local go!!). In comparision to my 24-70 and 17-40/70-200 mostly at f4 and the lengths of 24mm and 70mm.
I thought it was going to be the holy grail of light weight and stunning optics. it seems to be more ok weight and goodish optics. I was actually surprised that a five year old semi mashed up 24-70 at f4 was a we bit better in the middle and a moderate better at the edges on a 1dm2 than it. I kind of thought it would be moderately than the heavy fatboy. Oh well what I have is fine I was thinking of getting one for travel and it's still great but not as oolala as I thought it might be. I wonder how the micro focus might play a part in this stuff as the next camera purchase rolls closer. Maybe the next body has it as a kit at a deal. Eventually we will end up with one of everything....
ps IS can be handy inside but as always it's limited by subject movement, still if it's a 'free' add on I'll take it.
I did a comparison of the bokeh between the 24-105 and the 24-70, and found the 24-70 to be a bit smoother. Of course you can create bokeh with literally any lens, but in this case the 24-70 wins:
I agree that the 24-70 bokeh is a little better and smoother at the same focal length comparing f/2.8 vs f/4.
However, the point that many miss when making the bokeh comparison is that when framing the subject (like for a head shot) at 70/2.8 vs. 100/4, there is very little difference. Just look at Nathan Hobbs' shot above.
I love my 24-105 for wedding especially for low light contrary to most people’s belief. This one is at f/4.5. The bokeh is good enough for me. If I want something smoother I will go for my 85L or 100/f2.0
All these blanket statements as if ISO is locked as for film - Wow! We have three variables these days guys. Trading down depth of field for the sake of stopping motion (when brides want their processionals and recessionals sharp) is not necessary if you have a camera like the Canon MK III or Nikon D3. (If you are not making enough at wedding photography to stay competitive with current equipment, you might need to reconsider what you are charging, by the way.)
Solemn processionals aren't exactly track and field events. Stabilization is icing on the cake for everything else. You are using the latest pro equipment, right?
Another question is: Can you do your part to handhold down to the shutter speed that matches your ISO/ f2.8 combo? Camera shake can be a very significant factor in the tension and anticipation and haste of getting the shots - especially so to someone new to the business.
Test yourself at 70mm, on a 1.6x crop camera at 1/30 sec with your best low noise ISO, then take the same shot with a tripod. It's enlightening.