SCT devices basically all do the same. Some have canned and custom tuning, some just do custom tuning. Some are handheld programmers that can do some data logging, some have large screens to monitor and tune. Some monitor/tuner combos have touch screen, some use a smart phone or tablet BT connection.
Most go with a X3 or SF3 and buy a separate monitor like Edge Insight a CS/CtS, DashBoss for iOS, ScangaugeII, or Torque app. It's a matter of personal preference if you want separate tuner/monitor or a comb tuner/monitor.
Between this link and SCT website, you'll figure out which SCT device does what.
http://powerstrokearmy.com/forums/showthread.php?t=32970
