I bought the 30/2.8 not really because I wanted it, but because it was $130 brand new. I imagined if I ever bought a 12-35 or 12-40 I'd sell the Sigma. But now that I have it it's been the lens I use most often! It's very, very sharp! Now I'm curious how either of those expensive, top-performing zooms would perform vs the Sigma prime. If anyone has tried them both I'd be interested to see some real-world comparisons (at 30mm, of course, and preferably wide-open). Or, your opinion regarding using the lenses is also welcomed. Thanks!