Huh? Compared to what exactly? Man-pages compared to MS provided info are fairly exhaustive..

Now if we are talking of a documentation of a random project on github..

The BSDs. When I admined Solaris there was also very good docs.

The man depend on the utility. Except for the GNU stuff, where the man pages often tell you to look at the info pages.

Growing up on FBSD, it was quite the shock when I started working with RHEL/Debian. The qualitative difference between the manpages was disturbing.