The 50" Seiki is working great as a main display for Cubase. I use it for the project and midi windows, the mixer is off to the side on another monitor. I have not noticed any lag due to the monitor, but still experience Cubase-related slowdowns (the same as on a Dell 30") when working on longer (~2 hours), larger projects. No issues driving the Seiki, the Dell and 2x 24" off a single GTX 670, but have not tried PC gaming on the screen (it works well enough for PS3 gaming though - 1080P@60hz).