So far I'm really loving this lens, though I noticed when harsh lights are just right (usually at the edge of the frame) these rainbow flares pointed towards the center of the lens will show up. I've only caught it on maybe 4 shots so far and usually its when a bright white light is present near the edge of the frame. Here's probably the best example of what I'm talking bout. I actually don't mind it that much as it rarely happens and in some cases could just be cloned out, but was wondering if others have experienced the same with this. Aside from that, I love the lens, it's super-sharp for the price without being too rigid on the edges, and good accurate autofocus. (I don't think I'll ever get used to that rattling noise when the power is off on either the Sigma 60 or 30 though).