Managing transition from FPTP to PR: MMP vs STV trade-offs

[EricFJ]

I'm a policy researcher working on a comparative analysis of electoral systems, and I'm focusing on the practical challenges of implementing a switch from a first-past-the-post system to a form of proportional representation in a country with strong regional identities. My current case study is examining the trade-offs between a mixed-member proportional system and a single transferable vote system, specifically looking at voter comprehension, coalition stability, and local representation. For others who have studied or advocated for electoral reform, what are the most persuasive data points or real-world examples from other nations that successfully navigated a major systemic change, and how did they manage the transition period to maintain public trust?