here in NZ we use STV (Single Transferable Voting) for some local elections - it's one of the fairest systems around, especially for electing multiple representative (or at large) wards - but it is complex because it passes fractions of a vote around (if only a portion of your single vote is used to elect someone high on your list the rest is passed on down your list).

So it's very fair, all of your vote always gets used .... but complex - to the point that the law (these days a regulation) specifies the floating point precision (9 digits)

https://www.legislation.govt.nz/regulation/public/2001/0145/...