A complaint from the No camp is that second preference votes are counted equivalently to first preference votes when transferred, but is this a deficiency compared to first-past-the-post? Not when you think about how tactical voting currently works.
As a candidate in 2010, I had voters tell me “I like the Lib Dems, I like you, but I don’t think you can win and I really can’t stand Labour, so I’ve going to have to vote Tory I’m afraid.” Just a few minutes someone would be giving me the same spiel but about voting Labour instead. Now clearly in AV, these would be second preference votes for the Conservatives and Labour, but in 2010 these were counted just like all the other votes for these two candidates.
Yes, now you see it. First-past-the-post also counts second preference votes the same as first preference votes, but in AV it’s all done out in the open, whilst in first-past-the-post the candidates plonk their heads in the sand and pretend everyone who voted for them considers them truly the best for the job.
So another useless argument from the No campaign. I’m still waiting for one I can’t bat back, and as a nerdy computer programmer, believe me, my work colleagues have been putting all the strange and wonderful edge conditions fully to the test – and AV has proven to be superior every time!