After major down time with a small client using Exchange on their 2003 sbs, I did some research and contracted with 123together. We were able to get up and running again within the day. Their support is amazing when a rare problem comes up. The setup was very easy using their applet to change Outlook accounts. They also included an update of Outlook for each user. This was a great feature in getting all PCs on the same page. During the last few years, I can't remember any downtime at all. The control panel for adding or changing users is web based and very easy to navigate. I'd recommend them to any small business (those are my clients) to use instead of them running it themselves.