Specs are quantitative aspects of the option such as the price
Pros
Pro
Easy to use
Most Linux distributions that come with Exim, come with sane Exim default configurations. Changing default values and slightly adjusting configuration is relatively easy. On the other hand, building a completely new Exim configuration file from scratch might not.
Exim has by far the most flexible architecture of most commonly used mail transfer agents. As such it is a lot easier to break or do highly complexthings.