Haven't used the newest 24-70 2.8 L, but used the older one for years. Very sharp, rugged lens. I can't give it anything but praise optically. It is heavy, though, and lacks IS, and I just don't want to carry that weight around anymore. The 24-70 f4 isn't, in my opinion, as good optically...but it is still very good and I really appreciate the weight reduction.