Second monitor suggestions?

Hi, Ive just bought a new desk for the studio where I will have the room to setup a second display and Im just wondering for some suggestions on good ones to look at. Im currently using an 27"imac as my main display and would like another 27" that looks pretty comparible beside it. Ive heard the Viewsonic are pretty good because of the color sync and LG as well but dont really know too much about them tbh. Budget is flexible but would prefer not dropping $1000 if I dont have to. If thats the case Ill just buy the apple display. Thanks in advance and sorry for starting a new thread, but I didnt want to hijack another one!