Follow these threads and you will see many an open source ERPs being hammered for lack of depth, usability, completeness etc
We went down that path ourselves, trying to implement some of the leading open source ERPs for large clients (>10k employees) and realized halfway through we had to do a lot better to provide something that can be used by large companies.
Let me throw a challenge, how about this http://www.A1.iO, http://Academia.A1.iO;
Our promise is Depth, Ease Of Use, Open Source, but are we there yet? Let us know...
