My trusted wireless Logitech and Microsoft mice felt "funny" when using it on OSX and no matter what I did with the settings I could not get it to feel normal. I finally took a bit of time to look into this and appears that Apple deploys a different curve of scaling the acceleration curve. There have been several attempts to correct this with various apps such as ControllerMate, SmoothMouse, MouseCurves, but I found that the terminal fix to be quite adequate for what I need. Its no Starcraft 2 max APM precision, but enough for what I need on a dev machine.
defaults write .GlobalPreferences com.apple.mouse.scaling -1
This terminal command will make mouse movement much smoother and more familiar. To reset it, just replace the -1 with a 1.