To forestall any questions, no, I definitely don't hold the key forward any longer than what it takes to fire, and I always give it a little gas. I've had to replace the starter twice in the past 6 months. I've also replaced the alternator since then too.
Why the heck is this happening? Two starters in 6 months doesn't seem right to me.

Did you shim it properly? GM cars use shims to get the proper engagement with the flywheel. If the noise was different than the previous starter you may need them. I have also seen some low quality "remanufactured" parts. Perhaps you got a bad one. Good luck.

I went threw SIX starters in less than one month!!! I was not because I didn't shim the starters it was the crappy remanufactured starters. Spend the extra money on a new starter, thats what I did and never had a problem again

Damn, six.. Yea like said, I have seen some real crap sold as "remanufactured". New is what I always do if I can afford it.