I like having a wide angle a lot and I definitely like the 16-28 lens but carrying a 2 pound lens isnt the greatest. It was definitely a burden when I was traveling in Japan and those are the types of trips I like have a wide angle for. The 20mm Nikon is only 270 grams to the Tokinas 950 (plus its 3.5" shorter). Price-wise, they run about the same (Tokina is a few bucks more) so hopefully I could come close to breaking even if I sell mine and buy Nikon. Both are f/2.8.
What do you guys think? Right now I dont shoot enough to where its a big issue but I think it would be easier to take my camera places if I could transport it in a smaller pack and more conveniently. Do you guys think I will miss the 16-28? My only other lens at the moment is a 50mm 1.4