I'm running a Skyrunner Autarch every game I play. I think it's a great unit. He's almost exclusively my Warlord and that comes with its risks indeed. However, the key, as always, is how you play with him. If you send him in alone against a strong section of the table, then yeah, he's a goner. Really, he is not powerful enough on his own to take out a full unit. That being said, he can dish out some mean, highly versatile damage. The twin shuricats plus a lance and a fusion gun make for a lot of shooting, and those lance attacks in the Fight phase are very good. The trick is to use him in conjunction with another unit, typically Spears. Often though, I end up sending my Spears on their own - they are just so good that they can handle almost anything by themselves. My Skyrunner usually ends up charging a weakened unit on a section of the table that isn't strongly fortified. Sometimes it's a unit that my Avengers have shot at, sometimes it's a tank that's almost dead. And there you go - that's the strength of the Skyrunner Autarch: he can be used against almost any target(s), cleaning them/it up after something else in your army watered them/it down. Some units in the game are very weak in melee and can be locked from shooting by having the autarch charge them along. Tau fire warriors, for instance, can be completely disabled a turn in this manner, even if they start at full strength.
The key is making the most out of his speed to get into the right positions, as well as avoiding being shot at by more than he can handle. Sometimes, I screw up, sometimes I sacrifice him for a higher cause, but most of the time, I manage to keep him alive for most of the game.