For me Firefox is the better, atleast there is some source you can use
there, opera is directly trying to remove sources from the public, I
do not support that.

What do you want to support GNU (and freedom) or Open Source Movement
(and practical benefits ???)
I choose GNU even though there is some things you can't do with free
software just yet, but it is very limited and there is a lot of
practical benefits from free software (such as price) - can be sort of
commercial but it kind of misses the point that people should share,
so commercial would probably miss that.
Anyway support Gnu!
Ubuntu is a very much so Gnu distro [actually a gnu system with the
linux kernel]
so support Gnu - I think the creater of ubuntu made the point that the
system should be free (hence the choice of Gnome)
Gnome is partly written by Richard Stallman I think - at least he
wrote some parts of it or was somehow somewhere in the development
process.