I'll definitely try out Pumas some more if the situation warrants it. How do you think the Anti Infantry of the Puma compares to something like the Stuart or AEC?
It is inferior to those units, as it is a far better AT unit. But it will snipe models every few shots with the main gun - the coaxial is on the turret so it can negate cover without flanking too hard. Additionally, the vet 1 ability "aimed shot" will snipe a model (save for retreating squads).
Best use case against infantry/support weapons is to drive it right up to them (assuming no snare / AT) to negate cover and just watch the unit flail about or retreat.