Very sharp and affordable lens. Great for situations where you have some time to fous (as this comes only in manual focus). If you do get that time, the results are very good !
Here's a photo from a concert I went to recently.
When shot at 1.4, it also can have a very shallow depth of field. Things that are jut a few inches off the focus point will get blurred out, as seen this photo. This makes this lens one of the best for bokeh. and at a price that is hard to beat.
Overall, if you are shooting a subject that's relatively stationary, this is an excellent lens.
Here are some sample photos shot at night. Notice the extremely pleasant bokeh.