Summary: OK, so there's a simple answer to that question - because Nikon made the decision to no-longer have an in-camera focus motor on all but their very top-end DX cameras. So immediately, most of the market for this excellent, specialist DX lens vanished.
Summary: I was looking for a good quality telephoto with a fixed aperture for portraits, low light, etc. I couldn't justify the Nikon given the high cost, even for a used model. The Tokina seemed like a good compromise.
Summary: This is one of my "go to" lenses. I use it for indoor sports, low light, school stuff, and concerts, etc because of the 2.8 aperture and the zoom. This lens produces very sharp images and can give nice bokeh in the right situations.
Summary: I have had this lens for about four years, I bought it to shoot indoors for the concerts that i went to. It is built like a tank and with the 2.8 aperature it made shooting in a concert invirenment so much nicer without using a flash. My only wishes were that it would fit on my new 6d camera.
Summary: Some say the focus and slow and loud...I will say that it is not the quietest but it's also not the slowest either. Both factors are quickly overlooked once the quality of the output is seen tho :)
Summary: I wanted a 2.8 midrange lens to pair with my Sigma 17-50 F 2.8 OS and I wasn't sure at first but the reviews and rating got me interested, more than the Sigma 50-150 F 2.8 (See I could afford the Nikon 70-200 F 2.8 but the range is to far on my camera). So I thought I gave it a try.
Summary: I love the Nikon 70-200 f/2.8 but this is much smaller and lighter, and the range is perfect for DX (about 75-203 FX equivalent.) Too bad it was discontinued (I got mine used on Amazon.) If Nikon or Tokina made an AF-S VR version of this lens today they'd sell boatloads of them.
Summary: This is an outstanding lens with cropped sensor(it gives 70-200mm 24x36 equiv), who can easily be compared with the canon ef-70-200 f2.8, surely not usm, maybe smaller in focal range, but half priced, half sized, half-weighted.
Summary: I've had this lens for about three years now. I also own a Nikon 80-200mm f/2.8 D which is amazing on FX as well as DX. This Tokina lens is about half the size of the Nikon, doesn't focus as fast and costs considerably less. I would buy this lens again in a heartbeat.