I finally got around to finishing the Automatron quests. I've been playing off-and-on, because I started a new game just to try out the DLC, and I was seeing a lot of the same content the 3rd time around while I climbed my way up to being able to handle the DLC quests.
It's a somewhat short quest line, but the three buildings you enter are substantial, the Mechanist's lair in particular. It's definitely worth it if you're buying DLC individually, unlike Wasteland Workshop.
I kept Ada around the entire time, thinking she'd gain affinity and give me a perk like other companions. She doesn't. She's like dogmeat, completely nonjudgmental, but no perk for gaining trust.
She's also a bull in a china shop. I went Survival difficulty, no power armor ever, stealth for this game, and she was constantly revealing our position. Which got me killed about 4 times in the 2nd Automatron quest before I told her to stay put while I dealt with things more quietly. If you're tromping around yourself she's still good, since she's fairly tough and powerful, particularly if you upgrade her, and she carries a lot of stuff.
The deaths in the Rust Devil base were very frustrating, because I simply could not figure out how I was dying. Something was one-shot killing me, and it wasn't the hostiles. I now think it was the Assaultron Totem traps, but since the animation was just "you're dead" with no clear indication of why, I'm not sure.
The Mechanist's Lair was not too rough until the final confrontation, where they throw a lot of robots at you. I died once, but managed to live the second time, at least in part because I prepped the room with mines. Survivor mode can be rough since you can't heal quickly. I read afterward there's a way to bypass that combat, but I didn't find it on my own, and it is doable on the hardest difficulty.
On an unrelated note: Gun-fu kinda sucks. Spreading your attacks around is just plain bad tactics, it's unusual to have 3+ targets in VATS range, and one of them's probably going to move behind cover during the execution of the attack.
I didn't love the robot building aspect of the DLC as much as I thought I would. Upgrading a single robot companion is fine, but there's not a lot of reason to build a lot of robots just to do settlement work when new settlers show up for free via settlement beacons. Robots don't eat or drink, of course, so there's that. Building them just for settlement defense is very resource intensive if you give them halfway decent parts.