I have a Mk III with the 5-1/2 inch barrel, blued. I replaced the innards with stuff from Volquartsen. I'd done a couple of Mk IIs in the past and thought those were nightmarish. They're a walk in the park compared to the Mk III. However, with the work done, it's a pretty incredible little pistol. I can lean on the hard tonneau on my truck and whack bottlecaps reliably out to 75 yards .. with iron sights. I prefer the Mk II to the Mk III but this one isn't going anywhere.
I don't find either version all that hard to disassemble for cleaning.
One thing I don't like about either Mk II or Mk III ... I won't EVER holster one with a round chambered. Several times I've put the gun in a holster with the safety on and found it with the safety off when it came back out. That's too close to getting shot in the leg. It's a pain in the ass but I clear the chamber before I holster one of these ... always.
The only thing that could make me happier is if Ruger would bring back the 10" barrel.
Tom