I've owned the
Canon 10-22mm for over three years. I've also rented the
Tokina 11-16mm on two occasions for a total of about 4 weeks. The only other contender I know of in that range is the Sigma 10-20mm which I have not used.
From my experience I would say go with the Canon 10-22mm EF-S, hands down. It is overall the best lens from the bunch in my opinion. For a while there I wanted the Tokina to replace my Canon but after using both quite extensively, I'm set on the Canon. Here's the way I see their strengths and weaknesses related to eachother.
Canon 10-22 Pros:
- Lighter than the 11-16
- Wider zoom range, even the 1mm on the wide end is noticeable. The zoom on the 10-22 makes it suitable to leave on most of the time, depending on what you're shooting.
- Quite inexpensive to repair, Canon flat rate service is $85. I just had the front element replaced and a full CLA done for that price.
- Incredible flare resistance, I can usually shoot straight into a campfire or other bright source of light
Canon 10-22 Cons:
- Slower aperture and not fixed through the range of zoom
- Not built as sturdy as the 11-16 but also means it's lighter, still holds up just fine and I beat the crap out of mine
- generally more expensive than the Tokina (right now they're the exact same price on
Amazon)
Tokina 11-16 Pros:
- f2.8 fixed aperture
- Cool focus clutch system
- built like a tank
- kick ass sunbursts
- generally less expensive than the 10-22 (right now they're the exact same price on
Amazon)
Tokina 11-16 Cons:
- weight like a tank
- zoom ring goes the opposite direction of all of my Canon & Sigma lenses, kind of annoying
- limited zoom range, I didn't like leaving it on my camera for hiking like I do my 10-22
- Bad with flare, I had trouble pointing it even remotely close to a bright light without it flaring up big time
So with all of that said, the only real reason to go with the Tokina, IMO, is aperture and sunbursts. I've shot plenty of great night shots at f3.5. 2.8 would be nice, but not worth giving up the other features of the Canon. As far as the sunbursts, that is one feature about the Toki that I seriously love but again, not worth it overall.