Tau are good with mobile warfare, there not good at all with just stand and shoot, plus they have battlesuits to jumppack behind enemies and kill them. The biggest thing I've ever seen in Tau Technology are the Mantas, +50 weapons lol, luckly it's not meant for gaming, cause the Manta would own all with it's Ion blasters, missile pods, heat seeker missiles.
So what chapter is your marines anyway?