Tokina 11-16mm f/2.8 AMAZING lens. sharp, focuses fast, great for dim lighting (i imagine ireland has very dim days), great contrast and colors. Negatives, not much zoom range and can be between 600 and 700 US dollars. But even with the very limited zoom, it's still pretty awesome. Besides, when you get a wide angle, what's the point of zoom? The whole point is to get... a wide shot. I just wish they made a 10mm f/2.8 prime (that's not a fish eye). Would it even be possible to get as fast as 1.4 on a wide angle?
The sigma has more range, but it's also slower. Sigma 10-20mm f4-5.6. The positives, more range, and cheaper (around 450 US dollars).
everyone keeps telling me to keep my 18-105vr because it's such a great lens (for the price), but idk. ever since i got the tokina i noticed that with the 18-105 pictures look very... dull! the contrast and colors don't come out as vibrant. plus that (extremely) annoying distortion. I'll wait to get the Tamron...