Is the Xbox 360 headset good for singing(GH: WT and M) or should I buy the real mic?

I know my singing prowess is not as strong as James Hetfield, but I should be able to get the pitch right if I tried. I was using the mic because the game said I could use it, but the mic won't pick up my voice good. I'm always out of pitch no matter how much I try. Hell, I tried singing Rock Band on my friend's Wii(With the real mic) and I was better at it than using the small 360 mic. Any ideas?