Thank you for this. It makes me feel better.
My primary concern is that I'm missing something regarding the differences between the original version of the Tamron and the DX-II. The auto-focus motor is a big deal if you need it but since I don't, it seems to make sense to just save the extra $100. I just worry that I overlooked something else between the two.
I'll qualify this by saying I do not have direct experience with the two versions, but I really don't think there are any IQ differences to worry about between the two versions - I think you nailed it with the focus motor being the difference, so if you don't need it, I can't see any real serious benefits to paying more - the only difference if any will be maybe in motor/focusing noise and/or speed, but rarely is that an issue with a UWA lens.
I ruled out the two 10-24s because I read a lot of complaints about image quality - particularly in the corners. The convenience of the slight extra range (in both directions) didn't seem worth the potential trade-off in sharpness.
Gotcha. When I was buying my UWA lens, the Tokina wasn't yet available in my mount, so my comparisons were down to the Sony version, the Sigma, and the Tamron. I was down to the Sigma and the Tamron in the end - and own both brands of lens - but I found the Tamron to be a touch sharper on center wide open, better distortion correction, and more flare and fringe resistant, with the additional focal range just being a perk. The lens' worst performance is between 20-24mm range - which is fine by me since I bought it to use it wide open and at the widest end very often. I can't say I've had anything to complain about with the Tamron 10-24mm lens - sharpness has been very good for me across the frame, plenty usable wide open, and really crisp and sharp stopped down a bit. But that's just one person's word, and you have to go on the overall sense of the reviews and feedback you have seen - knowing that some lenses can be lemons in the batch, and some can be jewels in a batch, one person having an excellent or poor experience doesn't really give you a reliable sense of the lens - the average of 1,000 experiences is better - so if you've seen a larger number of mediocre to poor reviews, then go with that.
And remember there will always be some bad reviews for ALL UWA lenses - with at least a percentage of those being related to the difficulty of adapting to the UWA style of shooting, and not having perspective of how other UWA lenses will perform in the same scenario. My own experiences so far with the Tamron & the Sigma, and a friend who has the Tokina (older version), is that the three are really pretty close in performance, and if we took a bunch of shots from the three stripped of EXIF, we both couldn't tell one from another!
