+ Optically virtually without flaws
+ Great build quality
+ Both hood and cap very convenient
- In real world use not as small as pictures make you think it is (please read below)
I can be very short about this lens: It's virtually flawless. I have yet to notice any kind of abberations, the lens is sharp straight from f2.4 and the bokeh is pleasing. Depth of field, to me, is plenty shallow at f2.4. The build quality is, as with all Pentax Limited lenses, excellent. The cap and hood are both very convenient in use.
The only negative remark I could think of for this lens is that, in real world use, it is not as small as pictures on the internet might make you think it is. This is because of how the lens cap and hood work. The hood is of a screw-in type that telescopes out. The lens cap slides onto the hood. Thus, when you store this lens it will have the hood attached, with the cap on top of that. When taking photo's, it's more trouble to detach the hood than to leave it on, so why take it off. All in all, I don't see how this would present a problem to anyone, but it does make the lens about 1cm longer in all situations (about the same size as the DA15ltd), compared to when it is hoodless.