One friend of mine who does weddings, studio portraits, and used to do journalism, said that the new one will have no lead-glass elements because lead-glass is now illegal to manufacture. So he said I should keep my current Canon 24-70, regardless of whether the new one is a great lens or not.
I suppose I should try to find some documentation to back up his statement.

The older Canon 24-70mm f2.8 lens wasn't a favorite of mine. The two copies that I had at different times, both eventually gave problems .. softness at the wide-angle side; a tendency to back-focus or just grab anything in the frame, (although that could partially be the Canon 1D mk3 as well) ... and just that it wasn't a reliable lens. Both went in for calibration at least once.

I ended up relying on the 24-105mm f4 instead.

So hopefully the new Canon 24-70mm f2.8 fixes those problems.
(It's unfortunate that they existed in the first place though.)

With that then, it might be worth the higher price-tag.

well, with some hesitation i have one on order. we'll see.

You've ordered the new one? Can't wait to see some test shots!

One thing I ended up liking about the 24-70 is the placement of the lens-hood mount on the body of the lens, instead of the shaft (which was the same as the older 28-70). I know lens hoods aren't popular, but when i'm not using a UV filter I like the lens-hood for deflecting blows to the front element.
In the new 24-70, it will be wide at the short end, and long at the long end, like nearly all telescopic lenses in the world. The problem with this, as I see it, will be that the lens hood must attach near the front element on the shaft of the lens. That means, if you bump it (into a wall, or the back of somebody's head, a window, etc.) then your zoom length will be changed. In hectic situations this can happen often and without warning.

I haven't noticed any focus problems with my 24-70. That is, I haven't noticed any problems specific to the 24-70. I'm using a 5Dmk2, which definitely gets the gold medal for terrible auto-focus performance. All of my glass goes crazy on this body, but on my 60D, with the same number of AF points, the lens is fast and accurate. It might have to do with being an early adopter, as all companies, not only camera companies, tend to release things a bit before the last kinks have been worked out.

this is really hard for me. i got out of Nikon because of service problems and as soon as i got into Canon the D3 came out. now i am deep into Canon glass and the D4 and D800 comes out. Canon mean while is to my mind spending most its energy espousing the virtues of its video capabilities. i no longer offer video products but i do offer still photos. the custom functions menu Canon has should be one of Dante's level of hell. can't someone offer a dslr that specializes in photography? i have a 1Dx and and a 24-70 II on order. i hope that they are performers and not just a response to something that Nikon did previously...

I am speculating, but I think the Canon 24-70mm f2.8 II was probably a response to the Nikon 24-70mm f2.8.

It's funny you mention service problems with Nikon. Some people switched to Nikon because Canon had service problems. Nobody wins in that regard.

I don't think we're going to see a DSLR that only does photography nowadays. The average customer wants more features, so the companies are simply giving them the features.

Stephen, the Nikon 24-70 f/2.8 lens is 5 years old. That would make it a very delayed response. The Canon lens is 10 years old and has a mixed reputation. I suspect it's actually in response to the introduction of the 1D X and other cameras they've got up their sleeves. (hopefully a D700 replacement lol).

What surprises me is that it doesn't have IS while the 2 new wide angle lenses (24mm f/2.8 and 28mm f/2.8) do.

Not only does it not have IS, but it is lighter. In a backbreaking way, the heft of the old 24-70 compensated for its lack of IS.

Also, I think Canon is trying to spawn a parallel camera business that focuses solely on video. What is the point of an EF 28mm f2.8 when they already sell an f1.8? Image stabilization on such a wide lens would only be of use to people shooting video.

Allen,
It takes time to develop lens. Canon might have been resting on their laurels with the old 24-70mm when Nikon announced their 24-70mm. I cannot dispute your statement that they announced this for their new line of cameras, but Canon must have taken the Nikon 24-70 lens during their development of the lens.

it is surprising that the new 24-70L does not have IS and the two new wide angles (non L) do. a 24 and a 28? both IS, i suspect that they are aimed at video whereas the 24-70L is not. since i am an old guy i suppose i'm a one trick pony. i wish that still was one line and cinema was another. as to the Canon vs. Nikon thing, we i grew up with the:
Coke vs. Pepsi
Ford vs. Chevy
Democrat or Republican
it's all a matter of taste.
the best answer i can come up with is the one that feels the best in your in your hands and frees you to focus on what's before you rather than the device itself. in the end, it's about the finished works rather than the tools used. contrary to some popular belief, Di Vinci didn't have red stripes around the tips of his brushes.

For the Canon shooters. Here is an article containing the first (brief) hands on review of the new 24-70 II. It also has the two new primes stuck on Canon's new flagship camcorder.
http://dancarrphotography.com/blog/2012/02/14/hands-on-with-the-new-canon-24-70-24mm-28mm-is-primes/

I have been waiting for this lens for a long time. Very disappointed with the lack of IS. I would have purchased it hands down with IS based on the MTF charts. I will wait for the reviews and will have to think about it. It does appear it will have very good IQ. Tamron announced a 24-70 IS but I'm not sure how good the IQ will be. If better than my 24-105 than I may spring for that.