I prefer FLOSS .  You may prefer FOSS or OSS or something else.  That's alright with me.

The primary reason I prefer FLOSS is that people in the USofA are already familiar with the word.  People only need learn a new meaning to a familiar word.  There is no need for branding.  With FOSS or OSS the need exists to learn a new TLA or 4LA term AND a meaning for that term.  Plus, it is kind of catchy when someone says "FLOSS Today! ".  

And, FLOSS is used in official English-language documents in Europe, South America and Africa.

Many USofAans prefer FOSS to avoid confusion with the already existing English word FLOSS. Lots of words have multiple meanings in our language. To me avoiding FLOSS for that reason is just dumbing down of our society.

When I use the term FLOSS I essentially mean free software as defined in 1983 by Richard Stallman and I consider that to be open source software, free software, libre sofware, swatantra software, malayang software, and anyotherkindofsoftware that follows the four fundamental freedoms as defined in the Free Software Definition.