They're based on different technologies. Bolt uses B-Trees and Badger/Rocks/Leveldb use LSM trees.
Bolt also uses insane amounts of RAM and writes get slower and slower as the size of the database increases. (Personal experience, don't have benchmarks. Take this at face value.)
Bolt also uses insane amounts of RAM and writes get slower and slower as the size of the database increases. (Personal experience, don't have benchmarks. Take this at face value.)