Anything outside of Mail, CRM, Expense, Recruit, and maybe Desk is hair-pullingly terrible. They promise that all of their "apps" are interoperable, but these integrations are either half-assed to the point of uselessness or so full of bugs you can't rely on them.

Zoho Projects is the worst of the bunch—most of our teams are keeping secret Asana boards on the side just to avoid using it.