scarybob is right... when RIM's BIS servers go down, we have no e-mail, web, or BBM whatsoever (google RIM BIS outages and see how many we have had in 2010 alone...) I missed a few very important e-mails over the past few years due to servers being down on RIM's end and costing me customers in the long run.Distributed systems are inherently more reliable than centralized systems. For example, the failure of one or two worldwide servers could disable Blackberries worldwide. There is also the issue of communications. For example, the failure of a communications link could cause all communications in Eurasia to be disabled, not just communications between Eurasia and The Americas. With a distributed system, if each country or region has its own server, a massive failure in only one country or region would only affect that area.
I also have security and privacy concerns. Blackberry will most likely move their servers out of Canada at some point, most likely the US. Canadian privacy laws do not apply to databases stored outside of Canada. As the leader of a company or country, I would also be concerned about security. What political or business secrets are being stored and mined by RIM or the country where their servers are located and could that data be used or sold to undermine my country or company?