For ease of use, sticky strings every time. I also carry a Stop'N'Go kit, but I'm not convinced it's the dog's bollox from various experiences with it. Like finding the plug wearing down faster than the tyre, to a mate having to replace a plug twice on a 200 mile ride. I recently used two sticky strings side-by-side in a puncture on a chum's bike. It did the job (after trying one string), whereas I think Stop'N'Go wouldn't have touched the sides.