I have tried to search this comparison, but have not come up with much, so I apologize in advance if I have missed something. I have one of the older Sigma 24-70 2.8 EX DG lenses, and it has performed pretty well for me. However, with the prices on the Canon 24-105, I have been thinking about selling the Sigma for my first L lens. The Sigma works well, but sometimes I get the feeling the images are sort of flat without post processing. Maybe it is just me wanting something different, I don't know. We just had our first child, so the primary use would be general walk-around photos and baby/kid pictures with my T5i. I would like to have the ability to do some action and portraits, but I think I have that covered in other lenses. I also shoot in low light, but I think the flash would fill that void.
For reference, I also have the following:
-Sigma 70-200 EX DG HSM
-Sigma 10-20 4-5.6
-Canon 18-135 STM (Used mostly for video)
-Canon 50 1.8 II
-Canon 18-55 (Will likely be sold with my old 40D body)
-Canon 430ex II flash
Thanks id advance for the advice!