I have a MKI version of that in my safe. One of my daughters wanted it and I said "OK, it's yours," but there it sits, years later.
I came really close to sending it in to have the muzzle threaded last year, but things went sideways on that plan. If I ever get a 22 LR handgun again, a Ruger Auto would top my list. I've never handled the MKIV, so have no idea on a basis of comparison, but this MKI will spoil you. The Micro sights are very nice and the trigger was tuned by the old toll & die maker I bought it from many years ago. Bolt doesn't stay open after the last round and it has nine-round mags, but the way it shoots, I'd not trade it for another and take a chance. They did make a few nice refinements on them over time, even as great as they started out.
Dangit! I should have gotten that one out today! I had a friend over to shoot with today and anyone who shoots it suddenly wants a Ruger 22 Auto.