Yep, like people said above. CA is a lens property, some lenses show more CA, others less. Typically, more high end, expensive lenses will have less CA. But it also depends on the lens design, coatings, etc. CA is also not noticeable in all photos equally - if the photo is a landscape full of trees with leaves and no sky, you will see almost no CA. If you take a photo of three cones against a background, you will be more likely to
notice CA. Modern lenses are pretty good with CA, though. Pentax is really good with lowering lateral CA, but is known to have a little axial/bokeh CA wide open (again, not all lenses. Some say the reason for this is that axial CA correction can make the bokeh look worse and Pentax likes nice bokeh, even at the cost of lab measured CA scores)
There are a number of things you can do against CA btw. Pentax DSLRs contain lens profiles for all modern Pentax lenses (the ones with lens ID), so if you shoot jpeg, the camera can automatically correct CA, as well as other lens properties like distortion, vignetting. This takes a little processing power, though. If you shoot raw, the raw software (Lightroom, FastStone, Aperture,..) usually has some way to manually remove CA. Many software also support lens profiles, so you don't have to do any work.
CA is one of those things that can really drive a photographer mad, but most viewers will not even notice it. On digital cameras, there are a number of ways to minimize CA. If you worry about CA, check lab tests of the lenses you are buying, don't worry about the camera. Fact is, a good camera, with high resolution, will "capture" the CA in more detail than a low end camera with less resolution. Just like it captures more detail overall. The K-3 is no worse at CA than any other camera. Those reviewers did a poor job if they blamed the CA on the camera. I would not trust their opinions
Digital sensors can cause some optical problems, like sensor being shiny and reflecting off the back of the lens, but Pentax has not had any problems with this (and the lens is a big part in this problem, as well. Modern lenses do not have this problem)
tl;dr: K-3 does not have problems with CA. Some specific lenses (from all manufacturers) may have problems with CA. There are many methods of minimizing and removing CA.