Odoo is the world's easiest all-in-one management software. It includes hundreds of business apps:
CRM | e-Commerce | Accounting | Inventory | PoS | Project management | MRP | etc.
The report designer is available in v7. It's the module called base_report_designer.
It works on OpenERP online and on OpenERP On Premise.
By default, OpenERP Online use an OAuth authetification mechanism but you can also assign a normal password to your user to allow external plugin to connect to your instance. So, if you want to use the report designer in v7, you must assign a password to your user user the top menu:
More > Change Password