Shopping for email hosting

I mentioned in a previous post that I was shopping for project management software, and you guys really helped me out with a lot of great suggestions, so I'm going to try it again with another topic.

I'm looking for a hosted exchange server. I currently run CommuniGate Pro, and have for several years. I like it, I know the software, and it doesn't throw me many curveballs. However, we're moving towards a more Microsoft-centric user experience, for better or worse, and one of the things that is part of that is our mail server.

Since I don't have any Exchange experience at all, and my docket is pretty full as it is, we're looking for a hosted solution. A Blackberry Enterprise server is pretty much required as well, so is compliance (SEC/Sarbanes Oxley/etc).

One thing I've noticed while shopping is how low the guaranteed uptime is. The highest guaranteed uptime I've seen advertised is 99.9. That's ridiculously low according to enterprise standards. I suppose almost 9 hours per year isn't a long time in real-world time, but advertising only 3 9's makes me question what's powering their hosting server.

I do understand that uptime is relative, to a certain extent, but I don't want a hosting provider who just has a VPS at some other hosting company.

Do you guys have any suggestions? The companies I'm looking at right now are Intermedia, 123together.com, and MailStreet.

Interestingly, 123together has dedicated exchange hosting which they insist has a 100% uptime guarantee. I've talked to a salesman, who repeats this like he believes it, but I haven't yet talked to an engineer who can give me the actual estimate.

Of course, a dedicated hosted Exchange server is a wee bit more expensive than the shared hosting.


So, what do you all think? Do you have experience with hosted mail providers? I'd love to hear about it. Thanks a lot!