My main problem with STAR is that it seems to me like you should always give the highest available score to all candidates you don't mind winning and give the other candidates a zero, because you know there are people giving the highest possible score to your dispreferred candidates and you want to offset their score total as much as possible.
So I feel like strategic voting would mostly trivialize STAR into a form of approval voting, which would still overly benefit the powers-that-be since most people would approve of the established candidates while fewer people would approve of the other candidates, who might be able to eke out a majority in ranked choice voting since they might be higher ranked than the established candidates.
But maybe I'm just not seeing the other strategic dimensions to giving the middle scores to some candidates.
Edit: The link by @themeatbridge is a very good explanation of the benefits of STAR over ranked choice voting! I for one am convinced.
That's a viable voting strategy, if you're voting against one specific candidate. But how often does that happen, where a voter truly has no preference between two candidates? But that's hardly ever the case, and STAR voting strongly discourages running that kind of capaigning. Candidates want to build coalitions and find common ground, but also differentiate themselves without coming across as negative.
Nah, doing that will actually make your ballot less useful in cases where you approve of both the candidates that made it to a runoff round, because you ranked them both the same, and thus your ballot can't count as a "vote" for either since you indicated no preference.
For single winner this is will probably be a rare issue but for multiwinner, which is what I want, that could end up biting you as the margins close in for the last seat
Haven't done the math on how that would behave exactly, but you could effectively weight the rank of one group of candidates higher and one group lower while your total contribution is still the same, which has a similar effect as you mentioned with STAR but still forces a relative ranking to show preferences in between candidates you approve of and those you disapprove of.
Most any voting system would be better than what we have, but STAR is one that accomplishes the most. Several states and local governments have adopted Ramked Choice voting, only to face pushback when people realize that they still need to be strategic with their votes or risk being uncounted. With STAR, voters can be honest about their preferences, every vote is always counted, and there is less risk of spoiled ballots because of voter error. Votes can be counted locally and tabulated later, and fraud is harder to conceal.
Here's more info on how it works and why it's better for voters: