Opinions on UWA for Canon

I was basically just wanting to get any real-world feedback from any people out there with any of the following lenses.

I'm after an UWA zoom for my Canon 550D and have read tons of reviews, but real-world feedback is always good.

The primary options well within my budget are:

Sigma 10-20 f/4-5.6

Tamron 10-24 f/3.5-4.5

One that would stretch my budget:

Tokina 11-16 f/2.8

And of course there is the Canon 10-22, but I think that is a little out of my budget...

Any advice? Comments?

Cheers guys!