BMR does not mean single pass restore as such both products can do BMR (which is a term relating to the operating system recovery) If however you have an application like Exchange Server installed then SSR will get that back in a single pass restore with the operating system, but BE would need a manually created secondary restore job for Exchange.
However SSR cannot use tape or Deduplication and the Granular e-mail restore capability is better in BE.
Note if using BE to backup a Virtual Machine, then BE will also get back the operating system and application such as Exchange in one pass.
