Microsoft spend a small fortune on R&D, $9.5b to be exact (2010), that probably explains why they have been ahead in the software game for such a long time. Now I'm not saying that that amount is spent entirely on Project Server, but they do spend substantially on other solutions which integrate with Project Server and in the instance provide the basis for it, i.e. SharePoint as well as Home windows Server, SQL Server and the whole Office Suite and they are spending an unrivalled amount on cloud computing which is where technology is headed.
With that kind of investment and the fact that Project Server is now a mature solution, your organization can rest assured that they are investing in a stable and proven solution. In fact where to buy microsoft office have invested massively in ensuring that this latest version of Project Server is bug free from the outset, not only have Microsoft invested heavily of their own resources but a huge worldwide community has been engaged in the Beta test programme to ensure a reliable and problem free product from the get go. It is unlikely that competing products can match the investment or number of Beta testers that Project Server 2010 has enjoyed.