I've shot and been impressed by the Ruger Mk II, but the older examples I'm familiar with were a bear to reassemble. I have no experience with the newer models. So based on that experience would put the Buck mark slightly in the lead, however the Ruger will more readily accept optics on their basic model. I would say between those 2 that the accuracy edge would go to the one you were more comfortable with as they are about equal in mechanical ability.