I've ended up liking mine more than I'd anticipated. I thought the distortion on the wide end or the relatively narrow aperture would bug me-- and they have, at times. But for the most part, it's been my go-to lens when I shoot events. The 5D Mark III's high ISOs give me just enough shutter speed flexibility to freeze motion with f/4 at dimly lit press events and trade shows, and because the 24-105 range is so versatile, I use the lens at least half the time. I have to pull out primes if I want particularly striking bokeh but I've certainly found its sharpness, which is sometimes maligned, to be more than acceptable. Not as crisp as my 40mm f/2.8 or 70-200mm f/4, but otherwise as sharp as my other primes (though, to be fair, this is often comparing 24-105 at f/4 to 85 at f/2 and 50 at 4 f/1.6 or f/1.8-- not quite apples to apples).
This shot is my most recent 24-105 picture, nothing special, but I really like how the lens transmits colors, and how the Mark III's files respond to reasonable processing.