After much deliberation, and a good deal of internet searching, I weakened and purchased a Tokina wide angle lens for my Sony A200.
Made largely of plastic, but with a metal mount, the lens does have ED elements, and Tokina uses Hoya glass (I've always been a big fan of their filters) for relatively true colours.
It's also internal focusing, so the barrel doesn't change length when zooming, and the front element doesn't rotate - making the use of filters for landscape photography (my prime reason for getting this lens) a pleasant experience. That's pretty impressive for a lens that sits at Tokina's 'consumer' end, and cost me $200NZ in mint used condition.
From all that I've read, sharpness is decent, even wide open, but gets bitingly sharp at around f8 (as do most lenses) - perfect landscape f-stop territory. And although not a 'fast' or 'silent' focusing lens, it will be plenty fast enough, and plenty silent enough, for all the landscapes I'll want to take with it :-)
It's arriving tomorrow, so I'll get a chance to use it over the weekend (all going well weather-wise). Will then post a hands-on user report, with images. Can't wait.