What are the differences between MB and MA filetypes?

[tmtawadros]

I know that MBs load faster, and are smaller than their MA counterparts, but they are also impossible to debug. What I'm more curious about is compatibility between different versions of Maya. I've heard conflicting things, and everything on google is from 5 years ago. 

[damaggio · Accepted solution]

it doesn’t matter how old you read online about the mb and ma files, they are still the same and any information is worth reading,

mb files cannot be edited if there’s a problem, while  .ma can, in a  text editing program.

both files are compatible with earlier versions of Maya, except that you wouldn’t see any new features in the earlier versions.

[aerys.bat · Accepted solution]

.mb files are not backward compatible, but they are forward compatible.