A group of graduate students from the Lancaster University in Lancaster, UK contacted me last year regarding a research project they were doing. They wanted to compare open source and commercial ERP systems for the retail industry and evaluated opentaps Open Source ERP + CRM, openbravo, and Microsoft Dynamics NAV (Navision).
They were kind enough to share their results with us, and you can read it at Opentaps In Retail. I hope you would find it interesting.