I enjoyed that show quite a lot for the first few seasons, but like so many that start well it kind of lost it for me after a certain point.
There's cool site somewhere that has a real life doctor that critiques the medical realism of each episode of House, MD, but I was never able to find anything like that for GA… less of a concern for GA really, as with House the cases are much more central to the plot. However, there's an article on Slate where two real docs sound off about GA—you might not want to read it if you really love the show, but it does address the realism aspect to an extent, and it's definitely a very fascinating sort of review of the history of medical dramas in general.
http://www.slate.com/id/2126916/