For Surround, you only need the most basic HDMI-to-DVI or DP-to-DVI cable. No fancy adapter required and any combination of outputs works as you can verify here:
http://www.geforce.com/hardware/technol ... quirements (GPU Model: 970 | SLI Mode: Single GPU | Surround Mode: 2D Surround | Orientation: Portrait)
One great advantage of Surround is "real" bezel compensation: more pixels to make up for the physical gaps between monitors, whereas TH2G shrinks the picture instead and you get black bars on the far sides.
On the other hand TH2G being separate hardware is a bit more robust on the software side, but Surround is not far behind and you can have a centered taskbar, windows that maximize on a single monitor, a hotkey to "peek" at the bezel gap area etc.
To ditch or not to ditch depends on your day-to-day usage and habits I guess, but you can and definitely should give Surround a whirl.