Alright, so I know the debate when looking at a good WA lens.
What I want to get out of the lens is a good quality image, no excessive vignetting (which I heard can be a problem with the Sigma lens), no excessive color problems (which I've heard a couple times being a problems with the Canon lens), fast glass (duh, wider aperture), and a quality piece that isn't going to (for lack of a better term) rape my wallet.
I've almost completely ruled out the Tokina lens already just because of those other 4-8mm that it lacks. Though it's not the most important thing in the world, I would at least like to have the option to get something around 20mm.
And it would appear that the fast glass would be the Canon and Tamron both at F/3.5 over the Sigma which is a close second at F/4.
So as it stands in my head it goes like this:
Tamron > Canon > Sigma > Tokina
I put the Tamron on top of the Canon because for one, it is significantly cheaper, plus it gives me the added bonus of an additional 2mm that the Canon lens would not.
My biggest fear with the Tamron lens is that it will have a significantly noticable quality difference than the Canon/Sigma/Tokina lens. And I realize it is still a fairly new product, so I haven't found any trust-worthy reviews as of yet.
Opinions anybody? I know this is a quite popular debate between these lenses...but I just want to know what all of the pros vs cons are so that I can put my numbers together to see which lens has the best chance to make me happy with quality, price and whatnot and what lens is a sure-fire no-go in the photography world.
Any and all opinions are appreciated.