Originally posted by TropicalMonkey I have a Pentax K-5 and several Pentax lenses, that is more than enough for my hobby photography. But if I want to go a bit more serious, I can either stay with Pentax and get a K3-II or wait for the upcoming FF. Alternatively I can jump ship to Nikon or Sony. I like Nikon because it is prevalent and Sony for its mirror-less design.
If you like mirrorless then its time to go as it is doubtful Pentax will have a camera in that category for a long time.
If you like "prevalent" then sure go with Nikon. But what good is "prevalent"? If there is a particular lens that you need and Pentax does not have it, like maybe a 600mm f/4, then sure go with whatever brand you need to. But just because something is "prevalent" is meaningless. What are you missing with the Pentax line that you would use?
Arguing about minutia of camera performance is just plain a waste of time. There are no bad cameras out there today, you can get amazing photos with any brand. So find something that fits your hand well, has the lenses you need and fits your budget.
Pentax: well made, solid cameras, weather sealing, easy menu system, nice control layout, stabilization in body, limited primes
Nikon: well made, lots of choices in both lens and bodies, very prevalent so you fit in with the crowd
Sony: mirrorless, lots of full frame choices in bodies, can use most lenses out there with adapters at the cost of some automation
I've considered moving to a different brand several times. I actually had a Nikon D610 in my cart at Costco once. Each time I got the urge to change I went to a store and physically handled the other brands, spent some time fooling around with them, playing with the menu and controls. And each time, despite the reasons I had for considering switching I stayed with Pentax. My primary reason was simply that the Pentax camera felt better and more natural in MY hands. If that is not true for YOUR hands go with what feels good. There will be no significant difference in image quality anyway so I prefer to go with what makes me happy to be shooting with.