Spup is the generic name for puppies built with Slackware binary packages. The main reason behind Spup is binary compatibility with Slackware packages, and the Puppy Package Manager can install from any of the Slackware repositories. The foremost Spup right now is "Slacko", and is currently one of our official flagship puppies.
Upup (Lucid, Precise)
Upup is the generic name for puppies built with Ubuntu packages.What you get is a very small distro (the live-CD is about 130MB) yet with just about every application you would need and the speed and ease-of-use that Puppy is famous for. All of the advantages of Puppy, plus binary compatibility with Ubuntu .deb packages -- Puppy's own Puppy Package Manager will install any packages from the vast Ubuntu repositories!
Upup is a Puppy that has some compatibility with Ubuntu. Typically produced using
Woof with Ubuntu packages. Often they are named after the Ubuntu version name, for example
Upup it is your matter of choice. see this Why Slack instead of Ubuntu