Their APS-C cameras are fantastic. Their full frame camera is the best value for the money - almost half the price of the competition with comparable quality. Pentax has unique features for the enthusiasts.
But ... the ecosystem is dying. Sigma stopped making Pentax lenses. At this point I don't think anyone makes lenses for Pentax other than Pentax, and Pentax lenses are expensive compared to Nikon and Canon. So while the Pentax full frame body is an excellent value, once you start adding lenses to the picture, Nikon and Canon still win in the total cost arena. Pentax FF has very few choices of modern lenses. You could buy their film era lenses, but supposedly modern ones are a lot better in quality.
I'm a Pentax user. Used to by an Olympus guy. Kind of sucks to have to go through this all over again.
Pentax glass is really nice, I wasn't bothered about sigma. The more annoying thing is flash support always sucks for Pentax.
Pentax glass is great. It's also expensive! I want medium quality options.
They only just came out with the GR III (the II was almost no change and didn't do well).
Their design choices are baffling. You could set up the GR to have tactile physical controls for all the things you may want to change on the fly, but the GR III has a touchscreen instead. It also has a 30% lower battery life (which wasn't exceptional to begin with).
Though I suppose the USB-C port is an improvement.