I have more experience with CR CL than I do BC CL, but like with all resorts and CLs, there are various differences and a mix of pros/cons. I'll give you my random opinions:
BC lounge is a bit bigger, arguably more cozy. It has a better layout for food service than CR.
CR lounge has an AMAZING view, BC lounge has no view.
You can watch HEA from the CR CL lounge balconies and the music is piped in. Nothing remotely similar at BC CL.
BC has a better food and beverage selection, CR is good but limited variety compared to other CLs. Personal opinion of course.
With CR Atrium Club your room will be on the 12th floor, so almost the top floor (great views with both the TPV and Standard view category). At BC you'll be on the top floor, but height doesn't matter all that much (generally speaking) at the Epcot resorts.
The BC lounge closes between services and over night, the CR lounge space is always open.
We have had really great CM experiences at CR - have always felt at home there.
ETA: They do play the somewhat annoying “modern jazz” background music in the CR CL lounge. Not exactly my favorite. (I acknowledge that’s a really picky comment)
Here are some CR CL food pics from this past September in case helpful:
https://www.disboards.com/threads/d...-and-questions.3414590/page-589#post-58158505
Just one person’s opinion, but hope that is helpful.