In Belgium attendance is mandatory as well. I think it's a positive as it means complacency ("my side has already won, no reason to go out and vote") is never a factor in the outcome.
In Brazil as well. I think a good side effect, or perhaps the main intended one, is that governments aren't allowed to supress voters and have to make sure everyone has easy access to the voting booths. Every election there are mandatory pieces on TV about how people are voting even in the most remote of places.
