GZ3, nope,the glocks are not wimpy by a long shot..
It has a lot of composite in it's construction, but the slide and barrel assembly are all steel(natch..

)
I have put about 4 to 5 thousand rounds through mine(model 21 .45) and it still shoots as good as it did when I bought it new about 10 years ago. They handle abuse very well, I didn't clean mine for an entire year, just went to the range and shot it, and have never had it jam or stovepipe(partially eject spent case) on me.
They are not cheap either, I don't exactly know what the 21 is going for now, but last I looked, they were about 600 bucks retail.