Sous vide is an excellent cooking method for steaks. The general idea is simple to submerge the piece of meat in water that has the same temperature as you want the centre of the meat to have. By leaving the meat in the water for long enough (and making sure the water isn't in direct physical contact with the meat, only thermal contact) you can cook any piece of meat perfectly, because it is literally impossible for the meat to exceed the temperature of the water, making this an idiot-proof method for cooking the perfect steak.

The only disadvantage is that for the meat and water to reach thermal equilibrium can take a LOT of time (several hours), but apart from just checking up on the temperature every once in a while, you're not doing anything. Having a larger amount of water will make the temperature of your water bath more stable (you could potentially use a large insulated cooler, only adding some hot water to it every once in a while to maintain temperature) especially at the point the meat is submerged, since this will generally make the temperature drop quite a bit, unless the mass of the water far exceeds that of the meat (basic thermodynamics). Use a very hot frying pan/grill or a chef's torch to create a nice brown surface on your meat after it has cooked long enough.