The “old” Canon 24-70mm 2.8 L is a very famous lens. It covers the most important focal lengths needed for quick “everyday” photography and as such also HDSLR obviously. It is of great quality and lands on a professional DSLR shooters body very often.
Canon has just introduced version two of this lens and I’m sure it has a lot of optical features Canon has listed in their press release. That being said, I’d pick this lens any day, its predecessor has served me very well on the Scarlet-X short last month. In fact I’d need one tomorrow, but to be honest I don’t have the budget, Canon wants $2300 for this lens.
If you are on a budget, I suggest you save on lenses, there are huge price differences and there are some acceptable alternatives like the Sigma 24-70mm 2.8 for example. I’m not a fan of Sigma, but it costs a third. Or an EF-S like the Tamron 28-75mm 2.8 which is $424 at the moment.
My suggestion: Don’t let yourself be seduced by new products, check them out, test them or read tests before you buy. Do you really need it?