Have the fiskar and the olfa, and both have a tendency to " undo" themselves..like that dig-out isn't deep enough to keep them locked together. I have a really old gray , round on a ball bearing base, but it sort of dips in the center...
I did order the Martinelli from Walmart site, should be delivered to my local store by Feb 1, no shipping charge...can't beat that. Let's hope I don't get an email stating not available...has happened before......