One key differentiator is the limited set of languages Bond currently supports:
"By design Bond is language and platform independent and is currently supported for C++, C#, and Python on Linux, OS X and Windows."
Versus Thrift:
"language bindings - Thrift is supported in many languages and environments C++ C# Cocoa D Delphi Erlang Haskell Java OCaml Perl PHP Python Ruby Smalltalk"