The system's stability, ease of use (both as an administrator or end user), its ability easily integrate 3rd party applications via API connectors.
It has been very hard in finding any issues that are really not resolved yet by their support team - which means we can say it all works great so far! I highly recommend this product if you need some serious integration capabilities without having too much customization options available at your disposal when designing something from scratch yourself; otherwise there will be nothing wrong working with other systems such as Open Source projects like Odoo ERP but then again one needs more flexibility than what they get here already :) We have used pulp stream internally within our organization since last year now and everything seems smooth sailing thus no major problems occurred during those years while using it ;-).