i sold a sigma 18-50mm 2.8 and got this along with a Lowepro Flipside Sport 15L AW.
the sigma was ok. i think it was optically better too. what i could not stand about it was that it extended so much and the extension's build was toy like. I had it for a year or two and when i itched to replace it, i got the 24-50mm. i favor internal focus and internal zoom lenses, the affordable ones at least, and lot of those are by tokina (i have the 11-16 and 50-135.)
the 24-50, i didn't mind the 3.3-4.5 opening and told myself to use a speedlight (that's why i have several) when needed. the change in overall length was not so much and at its smallest, it would fit in my trouser pocket. the min focus distance was a joke but i had a nikon 5t which was a 62mm and fit its filter thread perfectly. distortion at 24mm is evident but nothing that post processing can't fix. same goes for the colors and contrast, i can set them in camera or tweak afterwards.