I am also a Tokina 11-16 owner and recommend it. But, from almost every review or comment I've seen, this is a case where you can't go wrong with any of the three popular choices: Tokina, Canon or Sigma.
As far as third-party lenses in general, I would say that you need to research the individual lenses. Some are excellent, some not so much. In the old days, you could pretty much be assured that if Canon or Nikon put their name on a lens it would be great. Unfortunately, that's no longer the case. Both have made low-end lenses that are less than great. (Although some of the low-cost lenses are pretty amazing values, such as the EF-S 55-250mm which is incredibly sharp, although not the sturdiest build).
With other third party lenses, I'd suggest you do the same as you are doing with the wide-angle, pick the focal length you are interested in and then read reviews to find the best value.