Ok, saw both. I feel it's really hard to compare the two because they're such different topics, but I guess what it came down to was Barbie is a fun summer movie type deal, and more or less what you expect, and Oppenheimer was definitely intense and we were glad we saw it in the theater (vs Barbie we probably would have been fine just watching at home). To drill down a bit (some minor spoilers):
- Oppenheimer is just soooo dang good at building suspense even when technically nothing is happening. Like, you're waiting for the Trinity bomb and you know what happens, but the cinematography and discordant music just draws you in and makes you feel so ill at ease, it's incredibly done. So that's why I feel it's a movie better suited for a theater, hard to feel it being so immersive when you're sitting at home on the couch.
- Bunch of nerds on this board so I'll say it, but I really liked seeing the portrayals of all these physicists from the age I'd only read about, plus a few Easter eggs along the way for those in the know (like young Feynman was at Los Alamos but not important, so they just show a guy playing bongo drums at the Christmas party). They did a nice job capturing the foibles of working with a bunch of physicists IMO- only inaccurate detail we caught was husband was NOT impressed at Oppenheimer's brief attempt at speaking Dutch, as it wasn't Dutch and sounded mainly just German.

(I did also like how halfway through the movie I turned to my dad and whispered "wait, is this the same Dr. Lawrence they named Lawrence Livermore National Labs after?!") Also, random, but some controversy in conservative Hungarian circles about the film bc they made Teller come off as such an ass. Pretty obvious to me if you think that you just don't know your history.
- Maybe could have cut a half hour off the end (or at least 15-20min) with regards to Oppy losing his security clearance, especially bc you have so many flash forwards in the movie to that point. Arguing over this and that in a back room just isn't as interesting as everything before it, you know?
- Switching gears, probably obvious but the closest parallel to the Barbie movie was the Lego movie, IMO. Probably not shocking when it's all about a toy and how ideas of the toys vs the real world interact. I feel like they had solid jokes as one wants from this sort of movie, and got definite creativity points for making it all work. My main criticism is they did such a great build-up of the concept, then I feel they didn't know how to end it so it fell flat, as can often happen in these movies. (Oppy's ending didn't fall flat, just kinda got a little long.)
- I genuinely feel anyone who thinks the Barbie movie is controversial clearly has nothing else going on in their lives and needs to get out more. Or has never hung out with a little girl in like the last 50 years if you don't get the juxtaposition of "Barbie can be anything she wants, but is also viewed as a bimbo, and oh yeah let's explore the part where Ken is just an accessory which is counter to how things normally are in the real world?" Really not ground-breaking material, folks.
Anyway, I think y'all would like Oppenheimer. I think for Barbie movie watch a trailer, and if you think it's fun check it out (but as I said, fine to wait for streaming). Not sure you have to for the latter if you don't want to see it.
Yes, I have a life. It's quite different from yours.