I voted for +4, for apparently the same reason some other people did.. playability and interchangeability with all my other bricks.
When Toys R Us had a sale on on the +4 Pirates line a few years ago, I bought 4 or 5 of the Captain Kragg sets for $2.99 each because I really like that little boat hull. I think it's pretty bad megablocks..
Playmobile had some pretty cool sets, but I never had any of them. One my friends growing up had the Wild West stuff with wagons and stuff, but there's no nostalgia there for me.
Oh, and I concur: Bionicle doesn't count as Lego