Looking for thoughts and comments from someone who has used both of these lenses. Likely getting rid of my kit 28-135 and looking for something in this range to replace it with to fill out my bag for now.

Yes I realize one is 2.8 and the other is 4. Not sure that matters to me as the indoor shots I use it for would likely have the 430 ex II being used anyway. In reality this lens will probably see more outdoor than indoor use anyway.

Leaning towards the Canon as the Tamron will not work on full frame. That being said, the upgrade to full frame is probably two years away.

Thoughts? Thanks in advance.