A bit worse, the missile precision is better and there are 3 missiles per salvo; additionally, they move and they can shoot in a straight line AND, unlike with the two other tanks, you're still perfectly unsafe if you get close and prone.

Couple all that with the fact that mortar shells really have to hit you dead-on to one-shot you, while the tank's missile have ~ double the AoE and knockback. Supposedly they nerfed them a bit, but I can't tell the difference from three weeks ago.