This isn't biased, those are plain facts. If you're going to accuse the authors of bias, at least detail your reasons for saying so, thereby giving them an opportunity to reply.
I'm a Domino Admin of 13 years experience and I admit I don;t know much about Exchange, and so I would love to hear some reasons from Exchange admins on why they think Exchange is better. Even on a purely email vs email platform, if that's what they'd prefer.
Here's some things I have heard about Exchange so feel free to rebuke if you can:
The jet-based data store is not designed to grow into the hundreds of gigs as commonly seen in modern corporate email systems. As a result, there are only two kinds of Exchange Administrators - the kind who have experienced data loss and the kind who soon will. I am sorry, but in todays corporate environment where compliance is often very important, you cannot afford to base your email system on a server that has such a reputation of being this unreliable.
We all know that Outlook/Exchange is far more prone to virus attacks than Notes/Domino. Apparently Exchange has more flexible anti-spam controls but Domino has good enough, and if you use a service such as messagelabs or mailcontrol you don't need that anyway.
You have to take the server off-line to backup the data store. I wouldn;t have thought this was true with open file backup clients so can someone tell me?
In my current job, we have a target of 99.9% server uptime during production hours - not including any scheduled maintenance/upgrades. I am sure that would be impossible to meet under Exchange but we do it easily. We cover Australia and New Zealand which includes several time zones so production hours is 13 hours per day. That allows for about 4 minutes downtime per server per week.
To my knowledge, the one thing MS does better, other than marketing, is integration, especially if your company is using microsoft desktops. Having the lions share of the market, 3rd party applications such as document management systems tend to build their integration into Exchange first and Domino is done almost as an afterthought. Having said that, if you are a SAP house do some reading on an upcoming product called Atlantic.