Its funny, one thing is to buy a metronome and use it and the other thing is to LEARN to use diferent timings on it. When you buy a metronome also you should learn how to play a single note each beat, 2, 3,4, and 12 notes per beat and when. There are really great exercizes for the knowledge of the metronome use that i found on the John Petrucci instructional video:
Rock Discipline, wich is the best for medium guitarists. It helped me 100%. If you cant find it look very hard for some lessons about it
