I don't like hospital dramas, however, when Grey's Anatomy was on, I watched it because Katherine Heigal was in it. I began to take an interest, but after a few seasons the characters became beyond annoying and I stopped watching.
I do love both but I think I have to go with Grey's I just love all the different characters and story lines. The gorgeous Drs are just the icing on the cake. Loved the whole thing about how they got together to buy the hospital to save it! Loved the two that died due to the plane clash but, wish they will still in it.
ER had more substance...Grey's got boring after 2 seasons. Even though ridiculous things happened on ER the writing and acting gave it more depth. On Grey's it seems ridiculous..oh, a helicopter crashed, oh...a ferry crashed...oh a car crashed..blah, blah, blah