I actually bought it for its ability to do slow motion video at 720p. I received mine today and had a play videoing a cat grooming itself. That wasn't very exciting so i chased it. It works well but i did notice the rolling shutter a fair bit. Will probably work well on a tripod. It was very smooth as you would expect. On my computer screen, it looked a bit pasty like you see with high ISO noise reduction but that is because of the high res computer screen and it not being full HD video. I would bet that it would look great on a TV screen. iMovie gives me the option to help remove rolling shutter effect.
The reason i bought it is because bands have been paying me to do promo videos of their live performances. I did one with the K5 i have linked here.
As you can see it is jumpy due to me making it 50% of the normal speed. My test confirmed that the K30 worked well. I will be doing some new ones in the coming month or two.
Hope this helps