When comparing Nitronews vs Mailgun, the Slant community recommends Mailgun for most people. In the question“What are the best services for sending newsletter/marketing emails?” Mailgun is ranked 6th while Nitronews is ranked 14th. The most important reason people chose Mailgun is:
Mailgun is included and configured by default in Meteor.js. So for projects which are built using Meteor, it's very easy to integrate Mailgun.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Free plan
With options of monthly or pre-paid plans.
Pro Customer support via phone
Pro Simple and Advanced mail editors
You can choose to use a Beefree or CKEditor to edit your messages.
Pro Tutorial for beginners until the first sent mail
Pro Integrates by default with Meteor.js
Mailgun is included and configured by default in Meteor.js. So for projects which are built using Meteor, it's very easy to integrate Mailgun.
Pro Developer-focused
Mailgun has a RESTful API with libraries and code examples in curl, Ruby, Python, PHP, Java, C#, Go.
Cons
Con Brazillian Portuguese only
As the time of writing(30/08/2016), the only language is pt-BR. Even though the support answers in English if needed.
Con Sub-par support
It has been reported several times that Mailgun's support is not excellent. Most of the time, they require a lot of time to respond to questions or support queries.