Good for portraits, indoors without flash
This lens is ideal if you are in an indoor setting and don't want to disturb others with a flash. Allows more candid shots to be taken as well since there is no flash. I noticed shooting wide open really narrows your field of focus, it's best to go to f2.0

Wow.. What a difference..this lens makes ...!
I bought this lens recently along with K200d. Have taken about 300 odd pictures, most of which are indoor shots. Coupled with the anti-shake of the camera body, and K200d's low noise in hgh ISO, the large aperture of this lense brings fantastic low light capability. If you still don't get enough shutter speed, resort to the built-in flash, your needs will be more often than not met.
I also bought the kit lens. Though a fairly decent lens by itself for a kit lens, I rarely use it. The 50mm Prime stays on the camera permanantly. I am glad, I bought this lens. At 0, this is cheapest quality prime money can get. I get biting sharp pictures with small apertures.
Great lens and a must for every Pentaxian...! I enjoy using this lense..!

Best lens I've ever used
To put it simply, this is the best lens I've ever used. Image after image turn out better than any other lens I've used -- including "L" glass from Canon! Beautiful bokeh.

Affordable professional lens
This lens has been a fundamental piece in my new photo portrait business. Great quality, bokeh, sharpness. I am very happy with it.

Just get it
Got it for baby portraits with a k200d. Amazing results.
Only draw back is that it gives you such shallow depth of field at 1.4 (which is a very very good thing), you need to be really precise in focusing.