Of the mass produced chocolates here, Cadbury's and Red Tulip are the nicest I think. Red Tulip mostly appears in Easter Eggs, Bunnies and the like. Nestle tends to be a bit fatty for my liking. Out of all the Nestle chocolates, I like the white and dark chocolates the best. They can be sickly too.
Mars Bars are too sweet for me too. Maybe if they put a strong mint flavour through it, that might cut into the sweetness a bit. I've never heard of lead in chocolate. I'd rather not know about these things as I worry enough already. Getting wound up about what might be in food would only be overkill.
There used to be a chocolate from Israel that was nice and used to be sold in Target. I haven't seen it for years though.
I haven't ever tried those chocolates mentioned in the first post here and don't think they are sold in Australia.