Best Open Source ERP
Opensource: today is a must for an ERP
Web-based: the only way to be used by everyone, everywhere
Solid: even if it is a rather new software, it has already reached a good level of stability
Big community: look on github
Too fast updating: Unfortunately, an ERP is a complex system and its most important capacity is to be able to adapt to different scenarios (each company has its own characteristics). AGILE and open source development pay the price of continuous updates that must be managed carefully, especially if you made low-level customizations.