I've had one since 2004. It's ok, just ok. Heavy, a bit soft for a prime lens, lots of ca in the corners. 17mm is the perfect focal range for me, but if I had it to do over again I'd pass. A 10-22 may be a bit more expensive, but it kicks the dogshit out of the tokina any day.
save your pennies for a canon 15mm (or the 10-22mm). if you cant afford it then get a sigma 15mm. if either of those are not worth the amount you make in tandems, then just keep the kit lens. i have had at least 7 magazine photos with the kit lens. it is just fine.
I found also reasonably cheap used Canon 10-22, just doing the $$$ math
Do the weight math while you're at it. The 15mm weighs about twice as much as the kit lans, and the 10-22 is another ounce on top of that. Also consider the size, the 15 is smaller than the kit lens, but the 10-22 is bigger than both of them, so the extra weight is hanging further out from your head.
Tokina is off then. We`ll see about the rest (canon 15/sigma 15/canon 10-22), depending on what I can find here. Everything is top-mounted on FTP so it doesn`t stick out. Thanks for the comments guys.
After couple of good tandem weekends ($$$) I have decided to go with new Canon 10-22. Now, here is the dilemma. For the price of 10-22 i can get new EOS 600D (T3i), with kit lens of course.
What will give me better results? New lens on old camera or kit lens on new camera?
My old 400D is still in reasonably good condition.
The body is as important to a photographer as a canvas is to a painter. The lens is as important as a brush is.
You already have a good canvas, changing to a sligthly better one wont make your paintings much better. However the brush you are using is too thick for tandems IMO. Its difficult to paint well with a brush that is too thick. You need the right tools for the job.
Changing from 18mm to 17mm wont make a difference, but the 10-22 will give you a variety of brush tools to choose from. Definetly go for the 10-22.
better glass is more critical then updating the body (in this case)
if you were considering a 5D MkIII then it would be a different story... but in this case with the smaller frame (APS Sensor) you probably won't see a substiantial difference between the 400d and the 600d.