If you understand Spanish, you should watch John Sudarsky’s video criticizing the current electoral system of Colombia (which is open-list* PR, including in the 100-seat nationwide district of the Senate), and advocating MMP.**
I offer for your viewing pleasure, not necessarily as an endorsement.
* Mostly. Parties have the option to present a closed list, and there are always some members of each house elected this way. But most come from open lists.
** The video and website only call it “mixed”, but it seems pretty clear from the examples given that it is intended to be MMP.