OpenERP is at the same time complete, standard, powerful, flexible, easy, supported, mature and open-source.
OpenERP covers all enterprise needs with more than 300 modules and more being developed every month:
Sales management
Purchase management
Accounting
CRM
HR
Marketing
Production
Project management
Services management
Inventory management
Management by affairs
Many more ...
It also supports nowadays best business practices: Just-in-time, FIFO, Average/Standard cost, MTS/MTO, Phantom BoM, Iso9001, barcodes, cost-accounting, ...
OpenERP uses a standard web services XML-RPC interface allowing to be easily integrated with other existing softwares (Joomla, Ezpublish, SAP, Ldap, Oscommerce, Office, Excel, Outlook, ...)

- With integrated business Intelligence, personalized dashboards for all users. Browsable and customizable graphs and statistics.
- Business processes can be modeled thanks to the integrated workflow design engine.
- Integrated Report design engine allow to create your own office documents and reports on the fly.

Applicative client interface Web interface
Supported- Biggest ERP community in the world of contributors, users, testers around forums, wiki, tinyforge, mailing-lists, openobject framework ...
- A worldwide network of partners, officially recognized enterprises providing local and vertical services.
- A great editor (Tiny company) continually growing and increasing its R&D effort, providing training, bugfix and support guarantees

Under the opensource GPL License, this not only reduces costs but also allows for a fast collaborative development with community contributions