[Xubuntu 13.10, ASRock Z87 Extreme 4, Core i7-4770, using on-chip Intel HD graphics 4600.]
I'm working with 2 monitors, a Samsung 2433BW connected to my mobo's DVI port and a Vizio E241i-A1 (TV) connected to the HDMI-out port.
My complaint is that the mouse has to travel a long distance after the cursor leaves one monitor before it reappears on the other -- almost as far as if there's a third (invisible) monitor between them.
Other than this, the two displays are working nicely. System settings shows the Samsung configured as 1920 x 1200, and the Vizio as 1920 x 1080. These are the correct optimal resolutions according to the monitors' manuals & I haven't modified them.