Best wide angle zoom lens for my nikon d7k?

Ok I need a good wide angle zoom lens for when i shoot landscapes. I can't decide if i want to get the Sigma 10-20mm f4-5.6 or the tokina 11-16mm f2.8. I would rather spend the around 480$ and get the sigma instead of spending 660$+ on the tokina but i hear bad things about the QC at sigma. I hear that some of the sigma 10-20mm are very sharp but some are soft and dull. Basically what im asking is it worth that extra money to get the tokina?