I've been wondering why I bought this model as I have used him once and think I know the reason why he gets so much dust. His Drive is good, but lets say you have the Syir and a Manticore. Now the Scyir isn't a weapon master but has flank, so in order to get the three dice on damage (4 if you charge) you need to have a jack be in melee range. So the jack has to get in melee before the Scyir activates. But if the Jack activates before the Scyir it's drive is useless as it will not need to re-roll nothing.
I'd say it's a good defensive ability as in you activate, drive the jack, then charge only getting the three dice. Then if you haven't killed everything and survive a counter you will end up getting 3 dice on a non charge turn.
I guess you could tack on a Griffon to his jacks and have it charge first, then drive, charge, then send in the heavy jack. But then you tossing a lot of points into a solo just to make him into a single sentinel......plus the drive for sentinels is way better....so why would I ever take this solo?
Just thinking out loud, anyone else have an opinion?