I think most people here use Canon L glass or the Nikkor equivalent so there may not be much experience of the lenses you are considering.

I have a cheap Canon DSLR (the 500D I think) with the kit lens on it. I use it only occasionally when I just need something lightweight as my Ds MkIII weighs a ton. The kit lens quality however is fine, even for stock, provided you aren't trying to use it wide-open __ which I almost never do for stock anyway as the DoF would generally be too shallow. I know successful microstock photographers who, at least in the past, used the kit lenses for most of their work.

The main problem with Canon kit lenses is not so much their image quality (at say f8 and above) but their longevity. You might only expect to get 20K-30K shutter operations out of one before the focusing motor breaks down. Then you have to throw it away and buy another. I do 40K-50K shutter operations per year so I'd probably be going through them fairly quickly.

Why not pop down to your local camera shop and try out the various lenses on your own camera? I think you might be surprised how little difference there really is in image quality between them in normal use. Honestly, from my experience as an image reviewer some years ago, I came to the conclusion that 90% of 'image quality' was actually down to the operator, not the equipment. Good photographers can produce wonderful, bright, sharp images using a Rebel/Kit lens combo whilst others would continue to produce rubbish even if you gave them a top-of-the-range Hassy.

I shoot with the Tamron f2.8 17-50. It's solid build lens and feels like that. Mine has survived a 2mt fall from my camera (didn't connect it properly) on a stone path. Although the front ring is broken (which is the only part that's a bit plastic/cheapish) it's still working great. The image quality is better then my Canon 10-22. The only down side for me is it's range. I think the Canon 24-105 would suit me better.

I own the 17-50, it was purchased to replace my Pentax Da 17-70 wich had an unreliable Sdm motore, wile I am still pretty sure the Da was a better lens I have to admit the Tamron is pretty Good, I miss a little more reach but the bigger brother while a highly regarded lens, on a cropped sensor will just be too long for me, rangig in medium telephoto lenghts without any wide angle.
Last thing to consider is that on my camera it's not really a 2.8 since it underexposes of about 1-1.5 stops.
Colors are good, no strange things.