I can't comment on user friendliness compared to Windows or OS X because I
don't use them. I can comment, however, that Trisquel is derived from Ubuntu
which has the reputation of being “user-friendly”.
I do not like the term “user-friendly”, but I do not oppose it on ethical
reasons. It is usually associated with an attitude of designing computing
systems so that they demand the least from the user (interest, knowledge and
effort), at the expense of flexibility, capability and control. It is not
clear that this approach ought to be called “friendliness”.
As an illustration: Trisquel has both a graphical installer which is
“user-friendly” and a text based installer that gives the user more
control, though it requires some technical knowledge about GNU/Linux (the
user must know how to make a sane partition layout, for instance). Package
management (installing, updating and uninstalling software part of the
distribution) can be done through a graphical interface which doesn't
requires any special knowledge, but there is also the text based “apt”
and ”aptitude”, and you can edit directly the configuration files with
any text editor and gives access to “advanced” features like version
pinning.
Most modern GNU/Linux distributions work “out of the box”, without any
further configuration needed to have a working environment ready for web
browsing, text editing, etcetera.
There are plenty of free as in freedom games, check Libregamewiki. Some
examples of well developed games are The Battle for Wesnoth and Warzone 2100.
