When comparing MIT/GNU vs Gambit, the Slant community recommends Gambit for most people. In the question“What are the best scheme implementations?” Gambit is ranked 4th while MIT/GNU is ranked 7th. The most important reason people chose Gambit is:
Gambit is fast/efficient, you can see benchmarks [here](http://gambitscheme.org/wiki/index.php/Gambit_benchmarks).
Ranked in these QuestionsQuestion Ranking
Pro Good performance
Gambit is fast/efficient, you can see benchmarks here.
Pro Can be easily embedded into an existing C/C++ codebase
Gambit has a built-in compiler that generates C code, which then is passed to your system's compiler which in turn compiles it to native code. This makes it easy to integrate Gambit into existing C/C++ projects.
Pro Very portable
It is very portable as it has no external library dependencies. It will build as long as the platform has a C compiler.
Pro Actively maintained
Con Not made to run as standalone
Cannot be compiled to a standalone executable, only to byte code that can be run from the interpreter; and cannot be conveniently interpreted by the interpreter from the command line.
Con Not very well-documented
The documentation is very sparse.
Con Poor Windows support
Con Ill-designed interpreter's interface
The interpreter does not support the use of the left and right arrows to move the cursor in the code and the use of the up and down arrows to navigate through the history.
Con Lack of SRFIs
Gambit natively implements few SRFIs. Additional SRFIs are available through the Black Hole and Snow third-party systems.
Con Documentation is poorly formatted
The Gambit documentation directs you to further resources, depending on what you're looking for. Because things are separated into different places, it can be difficult to find what you need.
Some documentation is only available in HTML or PDF formats that are hard to read/follow.