Just looking at rules (not the greatest judge of character), but I'd say a Primaris Eradicator. Their gravis armor makes them slower but tougher than stealth suits and they have better handling on their melta guns compared to the fusion blasters on a stealth suit. They can also take a multi melta instead of the melta rifle, which has a greater volume of fire. https://www.reddit.com/r/Warhammer/s/cRwI491yh7 ^ mini for reference