If IQ is brilliant, it would be a candidate for buying.
The EF 18-55 is an awful lens in terms of haptics - optically it is o.k.
I tend to see 70mm as a useful standard focal length, I love the 40mm
on APS-C bodies which equals to 64 in terms of 35mm equiv.
The 24-70 4.0 is light weight and might be my first IS equipped
lens. Additionally it bears a very interesting macro mode.
On APS-C: a 38-110mm equiv range is very versatile FOR ME
and on FF (if I change to that format) it is a good general purpose
If I go full frame it might replace the EF-S 10-22, the EF 2.8 24, the
EF-S macro and the EF-S 18-55 and makes choosing a lens set
Combined with the 2.0 100 it will be a fine two piece set of lenses
delivering high apertures where it counts: on the tele range.