I've had this lens for about 3months now. This is a great lens at a rather good price. F1.8 is really fast, and satisfied my desires for a fast lens for low light and portrait shots.
Pictures are crisp and sharp, almost unbelievably so, especially if you've grown used to the kit lens. You'll find that F1.8 gives way too much Bokeh very quickly. I don't go below F2 nowadays, and its still quite fast.
My only qualm about is the build quality. It's quite plasticky, and I'd recommend insurance on this baby. Mine is still great, but I handle it very carefully.