Platforms and sync: Clipster's biggest edge
Paste runs on Mac, iPhone and iPad. That's the whole list: there's no Windows app. Its sync goes through your personal iCloud, which is elegant when everything you own is Apple, and a dead end the day a Windows PC shows up at work or at home.
Clipster runs on Mac, Windows and iPhone. With Pro, what you copy on your Mac or your PC shows up on your iPhone, and the other way around: one clipboard across up to 7 devices, whatever logo they wear.