The biggest difference is that Slinkset is hosted whereas you have to host Pligg yourself, so Slinkset is going to be a lot easier to get up and running quickly. With Pligg you'll have full control over the source code, but we're pretty proud of how much control you get at Slinkset through an easy to use web interface. With this in mind it makes a lot of sense to at least try Slinkset first.

If you choose Slinkset and have any issues or ideas, we'd love to help out. Please feel free to email me: brett at slinkset.