I've been using Tuck alot myself.
That in-mission scouting of his is very useful. I can immediately figure out where any recharge stations might be, as well as see if there's any "potion" stations around that might help, provided I've run into that type before.
Not to mention knowing where the mission exit is. Usually I prefer to defeat everything first before leaving a mission, but if my Brawler has just melted himself for the 386319th time and my Science Exo is on fire (because of Science!!! of course), it's often prudent to make a quick exit.
And also making sure I dont miss any loot boxes is good too.