I strongly prefer RCV. Don't see the positive of tweet.
Canadian politics are already arguably broken in that party loyalty determines all votes, and riding issues don't matter, though rare stray votes do occur. PR makes this dysfunction even stronger in that the strongest party loyalty is the requirement for receiving an appointment. A possible positive is that someone really good at policy get appointed over someone really good at lying to public to get elected. But then why would a candidate help if there is 0 chance they will get a seat even if party wins, unless they get 90%+ of vote.
If a conservative won a seat through RCV in Toronto, they would still be in favour of Federal funding for Toronto. Similarly, an Alberta politician could like things that are good for Alberta independently of their party. Most FPTP races are decided with less than 50%, and under threat of wasting your vote on someone the least evil. RCV can change those dysfunctions. Under PR, who do voters complain to about stuff that should be done?
PR is such a drastic change with no obvious improvements to democracy.