I printed a dozen or so of the original design, and for the most part they've held up great. That said, there are some movie posters in 24x36 wooden frames that we put up in my cubical area that have managed to without fail break the original design after a few months. I even reprinted the original at 8mm thick, but they still snapped after a few months.

This is a trace of the original shape (so I've flagged it as a remix), but done in Fusion360 (since I don't have a license for SolidWorks at home).

This one is 8mm thick (vrs. 5) and beefed up in the two frequently broken areas (top front corner shears off and bottom of the hook sheers off 2x each in 4 failures). I'm printing this at 60% infill, bringing it to roughly 210% of the plastic of the original. Hopefully this one holds longer than a few months!