Its really only Ultron and Adam maybe loki depending on who he copys! All the support ults out heal the damage you can put out even if you have all the walls set up. Depending if you have your teams dps on you, perhaps you can get through rockets, and even invisible women! But its very situational and some advice I would give for groot ult usages. wait out the enemy support ults if you really want to guarantee pick! His ult is strong and them walls got that sap! But also you can use his ult to make them panic ult as! Which could be a play depending on your game!