Really, really good.
Its more expensive than other task management apps, but its powerful, slick, fast and syncs beautifully with the desktop and iPad versions. I use it to manage work and personal tasks, and short, medium and long term goals. I use it to manage project tasks, nicely compartmentalised into the correct categories and subcategories. I also use it to keep track of movies and books that friends recommend to me. I havent made much use of its geo-aware features yet - thats the next area to explore.
Omni make superb software and I can only recommend it! I believe that its software that is really worth spending money on.
Nixx0r about
OmniFocus 2 (legacy support edition), v2.5.3