@tromboads -- well, I have an Olympus XZ-1, an excellent shirt-pocket camera. And I've always been aware of the trade-off between physical size, sensor size, and image quality (at least until the new Ricoh GR) . So when the K-01 price went down under $400, I bought one. A quick comparison of K-01 test images on the DPReview comparison site will tell you why! Not just against my XZ-1... but against other APS-C cameras.
So. First, price. Second, image quality. But third, re the viewfinder, because the eye-level finders on DSLRs are just too small. Teeny. Now, if Pentax priced the K-5 IIs for <$500, of course I'd buy it... but not for the viewfinder. I'd want it for faster autofocus than the mirrorless K-01, mainly. And I'd still get out my gaffer's tape to attach a loupe to the back. Gaffer's tape, BTW, is the 'must-have' on any movie or TV set. Sticks, holds, comes off without leaving sticky residue. Get it at
Pro Tapes Pro-Gaff Gaffers Tape: 2 in. x 55 yds. (Black): Amazon.com: Industrial & Scientific. Worth every penny.
As for size, once it won't fit in my pocket, doesn't matter. And, a neo-view camera? More like an old Speed Graphic, where you composed the image upside-down on a very dim 4" x 5" ground glass -- but the camera was highly portable, for reporters, not just for the studio. And, back to viewfinders, Graphic users had a wireframe finder, for fast sports pictures. Later on, Kodak made a much smaller one for the Retinas... and it is metal, very well-made, and goes in the hotshoe of a K-01. KEH has them from time to time under 'Kodak Retina Prisms and Viewfinders'. Again, don't bother with it (or any hotshoe finders) for telephoto... but for wide-angle, it's great! Folds flat on top of the camera when you're not using it.