I'm gonna go with the Leatherman Skeletool... it's smaller and lighter than other multitools, and is extremely good at what it does. It has only the multi-tool features I *really* want, including excellent pliers with round coarse and straight fine gripping as well as wire cutting, an excellent high quality knife, two sizes of both flat head and philips drivers, bottle opening functionality, and a latch to attach it to your gear for easy access. The steel is excellent throughout (not just stainless), and working edges including the drivers are hardened... very reliable and practical multi-tool.
If you want allen keys: buy some allen keys. Paintball guns often require reaching hex screws at weird angles etc, only a decent hex key set (preferably ball end style) will do the job properly.