The main reasons for replacing groff were:

1. Groff is buggy

2. Groff is slow to compile & execute

3. Groff is not BSD licensed

mandoc has none of these problems. If you want a "generic" roff system, groff is available as a package.

According to http://mdocml.bsd.lv/

> groff amounts to over 5 MB of source code, most of which is C++ and all of which is GPL. It runs slowly, produces uncertain output, and varies in operation from system to system. mdocml strives to fix this (respectively small, C, ISC-licensed, fast and regular).