>>3286159The 24-70/2.8 is favored by wedding photographers who need the depth of field control for portraits in a wide variety of situations. It can be fun to work with these kinds of lenses for lots of other kinds of shooting situations, but if you don't know for sure that you need one, then you probably don't need one. The 24-105 is going to be the more useful lens, and like someone already said, the IS can compensate for more than the single stop difference between it and the 24-70/2.8.
>>3286164>5DII has high noise in the shadows, the sensor is not ISO invariant. The larger aperture helps going a stop lower ISO to lower the effect, but you will run into it a lot in post.This isn't quite an accurate description of the 5DII's shadow banding issue. This has nothing to do with shooting at high or low ISO; it will show up regardless of ISO setting, depending on whether shadows are exposed correctly or underexposed. Underexposed shadows will always have some red banding. It affects certain landscape photos where you might want to expose for the sky and then recover the foreground in post. Sometimes you can correct the banding in post, sometimes you just can't.
You can work around it by exposing the shadows correctly (doesn't mean they have to be overexposed, a proper exposure is all you need) and pushing your highlights, which you then can recover in post. It is not ideal, but as long as you know your camera's limitations, is not going to ruin photos unless you let it.