Originally posted by mischa72 I want to step up from my K5 to the K3II because of the better low-light performance, faster focus and higher shooting speed (raw fps).
Not sure what you mean with "low-light performance"; the K-3II will definitely be better at focusing in low light, both speed and precision, but the K-5 has better dynamic range and I think they are about equal for high-ISO noise (at same resolution).
The K-3II is a better camera overall. Not massively at any point, but slightly improved in a lot of ways. The speed of operation and speed of focusing the most notable to me - especially when picking up the K-5 once in a while.