@vermondee Performance of the 20mm F2.8 is considered to be identical to the 20-35mm at 20mm. If you can get them for the same price the flexibility of the zoom is a bonus.
@vermondee The lens is good for landscapes, because it doesn't have a lot of distortion. For group portraits, when stopped down, it is okay, but I wouldn't use it for tight shots because it can be a little soft at F2.8.
@RoRcrashslave The lens is a decent performer on the D700, that's what I used it on. The lens is best suited for landscape work, but does okay for general purpose wide shooting.
The lens is good, at least when stopped down to F4 or more. At F2.8 it is somewhat soft at 35mm. At 24mm it performs the best. I primarily used it for landscape shots before getting the 24-70 F2.8G.
@vermondee Tight meaning, not very good for close upper body portraits. This applies to just about any lens 28mm or wider (FX), due to the way wide angle lenses making people look unnatural. For group shots it's okay though.