You might obtain a sensible answer to your question id there were some indication of what you want this new lens to do for you that you can't do with what you have already.

I was at a wedding recently and shooting some pictures. I found most of my shots were taken Between 35mm and 125mm, so I was either changing lenses or just using what I had mounted and delt with it. I would like one lens that would be good for some portrait pictures and some candid shots without constantly changing lenses. So I was thinking of the Canon 28-135 zoom. What do you think?

Ah! Convenience. I guess it is important, but what if your taking pictures of another kind of subject, another situation? Usually there is some price in compromise, size and weight, or optical quality, or high price if not the latter, to pay for a do-it-all lens that covers too great a range of focal lengths.

To your original question, yes the 23-135 works just fine on a cropped sensor camera like yours.

I own this lens and it works great with enough light. Indoors I find that I have to use an external flash with it to get a decent exposure.