I'm using this on my Nikon F100 35mm camera and I love the wide angle nature of the 24mm. Also I REALLY love that I can focus on something about 3 inches away form the lens.The depth of field looks beautiful and smooth. I think the lens is built pretty solid, maybe a step down from my Nikkor 105mm in heftiness, but I have no problems with it.
There may be a bit of magenta fringing on one of my photos, but I can't really tell if that was the lens or the light. All other looked great and sharp wide open.
That being said, I evaluate a lens on the creative possibilities it opens for me. I don't really focus primarily on technical aspects like most other photographers. Personally I have never thought, Oh I'd would have loved the photo if the focus were sharper because I'm typically looking for something more than technical perfection. I know this is a purists and perfectionists medium, and that it really easy to get caught up in. So if that's the case, money shouldn't stand in your way. But for me, I love how my photos look, I think the price is great, a small price worth paying for the creative opportunities it opens for me.
Recommended for artists, maybe not scientists.