Focus Peaking is the major reason I finally went digital with a new K-01. This in large part as I only plan to use my nice collection of M42s - bought when I bought my last new Pentax, a Spotmatic ES II 'some years ago'.
Previously, I have been looking at everything since the K-x, but since I was always going to be manual focus, always decided against.
The K-01 and Focus Peaking changed the game. A few weeks ago I got just the K-01 body, and 'permanently' installed the 30120 adapter (previously bought some years ago from Adorama when they had them).
Lots of fun so far - and for me - Focus Peaking is just great! While I have not had much experience with wide angles or tele lenses yet - I'm finding my old ES 1.4 50mm SMC Tak works super with the K-01 - though when there is a lot of light I often switch to my F4 50mm SMC MACRO Tak with its brilliant color, contrast, and sharpness.
I'm also starting to use my mint Makro Kilar E 2.8 40mm Preset, which I never used on the ES-II because I was scared of the mirror crashing into the lens when used at or near infinity. This is a super-light Tessar formulation, and of course gives me a more 'Normal' lens. And with the K-01 - no worries about mirror crashing
Also finding that with M42s and the K-01 - the old Presets like the Kilar, at least for me, are a bit easier to use than the newer Taks with the A/M switch. Easier to move the preset ring, as far as I am concerned. This led me to just buy a copy of the original preset 50mm MACRO Tak.
Seems unbelieveable Ricoh/Pentax discontinued the K-01 so quickly. Its perfect for me. And who knows how much better a 'K-02' might have been...
Just like shooting my original ' Spotmatic - but no 'match needle' on stop-down or fiddling with shutter speed dial. Float the ISO from 200-3200, focus open, stop down, let Av do its thing.
Mulling getting a spare new body to put away..
Chris