Personally, I would always recommend reading them in order of publication, bc that’s the order AR explored the characters and their stories. And some things may be mentioned in B&G that would spoil TVA. 

TVA has a lot more of the problematic stuff re: Amadeo/Marius as a ship, so if you’re not interested in that, you might want to avoid it entirely. 

I admit that I like Armand more as a character than Marius, I enjoy his voice, the framing of that story in terms of what’s happening with the other characters at that point in canon, and TVA obvs has more focus on Armand, and, I think, TVA is a better story overall, so I prefer that book entirely, but that’s just me!

Anyone can add their thoughts on this, too 😀