Hi there, in the world of Mac, i'm effectively a novice, and i am about to buy my first mac ever in my life. I've been interested in 27" imac and 15.4 rmbp, but i'm not very clear how is the display screen of the imac model in actual use. Compared with RETINA display of 15.4 macbook pro, how much differences between them and whether it is worth buying? Your answers will be pretty helpful. Thanks.