To the original poster, you don't need anyone to convince you anything. If you have your mind set on leaving for faster AF and some such, go right ahead. No statement from any forum member here would convince you, otherwise you yourself are not sure what you want from your photography, and I'm pretty sure you know what you want.
Others here manage multiple systems, though I'm not too sure if you'd want to justify the cost of doing so.
Me, I find it amusing how people carry on the same whining about the AF system of Pentax.
Could it be better? Sure, but for my own personal needs, it's not much of a deal-breaker for me, compared to the cost of maintaining a Canon/Nikon/Olympus/Sony system. I'm not a professional, so I imagine that others would be better served by moving on since they do depend on that for a living.
I'm honest with myself that I don't have money to throw at the problem. That said, I'm also open enough to learn workarounds to the problem, and so I don't feel as disappointed as some others are here, to the point that they devote endless minutes of their lives complaining instead of moving on to a better brand for them and taking pictures, which is really the point of all this. I've rarely used all AF points in my camera, I have no qualms about looking for a high-contrast point in a low-light scene, and I haven't also any problems resorting to manual focus.
I fully respect people who need or want faster AF (and FPS, to include another sore point here), and I hope Pentax and Samsung address the problem in their next cameras. That said, Photokina would be the next show where we could take a peek at what Pentax/Samsung has been doing, and it would even be a longer wait for the next camera with improved features to be available. If the need and itch to switch is there, by all means go ahead, especially if paid work requires it. Any DSLR today is capable of getting good pictures, and cameras today differ more in other aspects like AF, FPS, ergonomics, etc.
Me? Being the amateur photographer that I am, I'm happily gonna chug along with my K100D Super and kit lens, while saving money to buy a Sigma 18-50 2.8 lens.
Best of luck with your decision.