I have an EF 17-40 f/4 L, an EF 70-200 f/4 L IS and an EF 100-400 f/4.5-5.6 L IS in my Lowepro Nature Trekker, but this lens is what's attached to my EOS-5D most of the time - and whenever my 5D is stored in my backpack when I'm out and about, it's stored with this lens on it. That's about the best recommendation I could give.
The zoom range is great for everything from architecture to landscapes to portraits and it even performs nicely with either of the EF extension tubes (12 or 25) attached. Even without them, it focusses up nice and close to 0.45m - only very marginally outside the 24-70 f/2.8 L's closest focussing distance of 0.38m (which I'm guessing is probably the other lens you're considering if you're taking the trouble to read this).
OK, so it's not as fast as the 24-70, but the better zoom range, the 2nd generation IS (which is worth 2-3 stops on a good day - i've taken some acceptable shots hand-held at 1/15 sec) and its size (107mm versus 124mm) and weight (670g versus 950g) makes this a much better lens - for me anyway. No savings on filters though, as both lenses are 77mm diameter front elements. The fact that the 24-105 f/4 L IS costs about £140 or so less than the non-IS 24-70 f/2.8 L is actually only incidental and shouldn't influence you.
So if you're a slave to aperture, go ahead and get yourself the 24-70 f/2.8 L, but if its a great all-purpose lens that doesn't weigh much and fits in an average SLR zoom case, get this and go somewhere nice to take some great photos with the cash difference!
To summarise, this is an excellent all-purpose wide-short telephoto zoom lens with the image quality you'd expect from a Canon L series. Very highly recommended indeed.