It doesn't fix the spoiler effect (it makes its own version of it: https://en.wikipedia.org/wiki/Center_squeeze ), and it removes monotonicity. The second one is a big deal for me, at least in FPTP a vote for a candidate always helps them. With RCV, a vote for a candidate can hurt them, and sometimes not voting makes the outcome you want more likely than if you did vote for it.
The 2022 Alaska election was a great example of it failing: https://realrcv.equal.vote/alaska22/ FairVote called that election a success because people managed to fill in their ballots, even if they didn't get the outcome they thought they were voting for.
I've seen discussions around how it can be more confusing than the current system, and can reduce confidence in the election.