Can't answer specifically for the viper, but I can tell you that the Strike Eagle's is pretty simple as well - just push a button, it turns on, and you're hands free. It's got a couple different modes - you can have it hold altitude, or you can type what altitude you want it at, and it will fly to that altitude and level off. As far as using it in formation, it's not impossible and it can come in quite handy for tactical (about a mile wide spacing) formation. Get yourself level with your flight lead, smack it on, then just make tiny heading corrections to maintain your spacing.
The E model also has terrain following radar that will keep it at a specified AGL altiude. When coupled with the autopilot in nav mode, the jet will fly itself low level. When it reaches a designated turn point, it will turn to the next point and maintain altitude. The only thing the pilot has to do is tweak the throttles to maintain airspeed.