I read The God Delusion and wasn't impressed. You're much better off reading Dennett if you want atheist polemics.
The main issues with it were:
a) He made bizarre assertions about history that were blatantly false
b) Spending pages and pages attacking strawman arguments for Christianity/God and then ignoring most of our top guys. I think he spent like two paragraphs on Aquinas, but a heck of a lot more on Tim LaHaye.
Of course many scientists avoid getting involved directly in religious controversy and some do believe in God, but since science has historically been attacked by religious people, I think that it entirely appropriate for scientists to be critical of religion. Religion should not have the special protection that it has.
Atheists are to history what Baptists are to biology.