Over the last two weeks, I've been looking at different technologies to help further organize my life. After being a loyal Toodledo user for years, I've looked at a million task managers. Finally, I settled on Producteev. Cohuman and HiTask both have some really interesting ideas and could develop into strong contenders. But Producteev is the most usable right now (lack of a native iPad app notwithstanding).
Why switch from Toodledo? Well, I was looking for something more collaborative. All three products listed above allow multiple people to work together on tasks, assign tasks, and converse as the task progresses. Been using it for a week and have noticed a big difference.