Landscape lens choices

I'll start by apologizing for repeating this question because I know I've seen it here before. I've recently had a chance to see a Canon 10-20 lens and was wondering if anyone has had experience with this lens and if there is a cheaper alternative for landscape shots.

I am extremely happy with my Sigma 10-20

that is a good super wide lens. i've heard that the 17-40L is a good landscape lens and it is about the same price new. of course it isn't quite as wide, but i've seen photos with this lens that are amazing. you have a 17-55, so i don't know if you think that is wide enough or not. if you want wider, the canon 10-22 is the way to go.

Tokina 11-16mm f2.8, faster, cheaper, equally sharp.

My Sigma 10-20 lens is great and a lot cheaper than the Canon equivalent.

I now have both, Tokina 12-24 and Canon 10-22... I think they are about the same, but I like the feel of Tokina better. I'm selling my Canon if anyone is interested...

tokina 12-24 which was a nice lens. also the sigma 10-20, but had 3 of them due one side or the other being soft. the 17-40 worked very well. now it's just the 24-70 on a 1.3 crop and I'm very pleased with it.

I had 17-40 on 5d... works really nice, but not wide enough on 1.6 body!

Yuriyo, is the 17-40 your go to lens on a FF, for walk around and landscape, or...?