Its good (very good)...

It is a fine outliner, and having the web interface is fantastic. Ive been using this since it first came out and the web interface since they added it. Ive tried others but always come back to the simplicity of CarbonFin Outliner. And its like fort knox, Ive have outlines that I created back in 2011 still available.

dgerton about Outliner, v3.7.1