When GMail is so widely used as well as all of their products, Why do you think so many people are down on them? Is it because of the reality or perception that thay read your mail or gather personal info from you?
They do data mine gmail... I've sent things via gmail that mention brands, or specific products... and the next time I hit a Google site, guess what shows up in their Ad sidebars... stuff I mentioned previously in gmail.
I honestly think most of it is just that people like to complain. It's the "cool" thing to do. We know that Google data mines, they don't even hide that fact. Unless you're rolling your own email, I don't think you can be down on a service that works so much of the time.