There is an online help authoring tool popularity contest
being conducted by Char James-Tanny of the HATT mailing list.
Personally I find these surveys kind of silly because they are not
statistically reliable. Nevertheless I am unabashedly voting for my
favorite, Adobe RoboHelp
and suggest you do the same if you are so inclined.
The survey (short and easy to fill out) will be open till the
end of September.