Dawkins is a good author. There are many other great atheist writers out there as well, so Dawkins isn't the only game in town. I really liked Sam Harris's "The End of Faith".
I liked Dawkins story because it showed a path to atheism that is perfectly rational and not the usual "mad at god" accusation which many critics of atheism use in order to downplay the seriousness of one's personal faith journey.
Collins is interesting because he came at it from the exact opposite route which I find quite interesting (especially since not all of CS Lewis' arguments for God are less than great). Of course he was working initially in the quantum world so he probably saw some incomprehensibly weird stuff. But really sounds like he came to Christianity from the same position that Dawkins started off at: wonder at the universe.
In my personal opinion, the route Dawkins took is far more "scientific" (pare out those explanatory variables that are not needed) than Collins. Not that I think Collins is a bad scientist or anything. Far from it. Collins came up against the wonder and felt there was a need for some other explanatory variable. It just so happened that he was able to find it, out of all the different conceptions of God, in Christianity. Even Murray Gell-Mann leveraged the 8-fold way of eastern religion to help him start the standard model in physics.
Religions seem to fill a very important need to the human brain: putting some "face" on the unknown. While the scientist waits for the explanatory variable to reveal itself the person of faith finds those things they cannot immediate understand and "explains" it with something that feels like it answers the questions (even if they cannot be shared by all observers).