Getting OT - it depends on the arena design. In Australia and the US, arenas have little to no 'throw out zones' so flippers have a much harder time winning. I haven't been following the US Sportsman bots but here in Australia, axes and lifters do very well.

Back to hovercraft bots: another drawback is trying to reverse them. Its possible to turn in their own length but a proper reverse takes a lot of extra engineering and weight.