I had - and sold - a K-30 a couple of years ago. Since then I have also had and sold a K-S2. I much preferred the K-30! If I had the money I would probably get another K-30 and invest in a few Limited lenses, including the 20-40.I rented a DA 20-40 once back when I had a K-30. It was good enough that I was tempted to buy one, but the K-30 really wasn't the right camera for me.
I agree with all your points, Steve - especially the ones about the superb image quality. Most of my recent shooting with my own recently acquired KP has been done with two of the small Pentax DA Limited (Ltd) primes - the 21mm and the astoundingly tiny DA 40 - and the images I'm getting from them, coupled with the KP's underrated sensor, continue to surprise me.I've been a Pentaxian for a long time. But my Pentax gear hasn't gotten much use in recent years, amid all of the excitement of mirrorless. I've felt a bit bad about my Limited lenses getting no use: The 20-40mm zoom and the 15, 21, 35, 40 and 70mm primes.
Frankly, as good as the full-frame K-1 is, I haven't really been tempted to buy in - not only because of the cost of the camera, but the need to purchase at least a semi-decent collection of full-frame glass for it.
But then, this Christmas, Ricoh Pentax put the KP on sale for $698 - directly from them. And I pulled the trigger. It's perfect for the Limited lenses I've listed above. And the best part is, I don't have to buy even one more lens.
And the KP has already reminded me of many of the things Pentax brings to the table: Extremely rugged build, weather resistance that may very well be the best out there, excellent viewfinders and tons of little features and design points that remind you the camera was designed for serious photographers.
Image quality is superb for an APS-C camera - probably equal to the Fuji X-T3 - with outstanding high ISO performance. The Pentax DA Limited primes, while optically excellent, are not known for being the fastest glass around. They run in the f/2.4, f/2.8, f/3.2 and f/4 range. This is where the KP's clean files even at higher ISO's really shine - making up the difference for slower lenses.
Battery life isn't anywhere near what you'll get on a K-1 or K-3. But, then again, it isn't any worse than you'll get on with most mirrorless cameras.
Many Pentaxians complain about continuous autofocus on most of the brand's modern cameras. But, again, it doesn't seem to be any worse than what you'll find on even the better mirrorless cameras - short of Sony's eye focus.
Overall, I'm pleased and mildly surprised, given some of the reviews and reaction to the KP when it first came out. To others, I say don't necessarily cross Pentax off your list if you're in the market.