Santa Fe was forced by the courts to use IRV, they were sued by FairVote from the Washington DC area. Santa Fe had to spent $350,000 on "voter education" for an election with a bit over 20,000 voters, which is over $17 per voter for "IRV EDUCATION". Even with this $17 per voter price tag, spoiled ballots went up over 650%.
A Sample of the over 900 Actual Spoiled Ballots From Santa Fe, an increase of over 650%.
Not as easy as 1-2-3.