Ehhh, grinding out Void Thrashing feels a little easier with Sky Furies than with most other units I find. They’re fast with the upgrade, and at level 2 they do something like 200 damage per shot. Plus, you can transform them to take down the big Hybrids.
But in most cases rocket troopers solve everything. Mengsk P2 is actually my least favorite for this reason - it’s somehow less effective at being a Royal Guard build because you need those extra minerals for rocket troopers.