How to send monthly newsletter if the site is complex and has a lot of content types? I want to send monthly newsletter to subscribers via Drupal. The website has lots of content types (news, events, books, courses, blog posts etc.). If the site has only one content type it would be easy to prepare this newsletter with Simplenews module or Mailchimp etc.

Because the site is so complex and needed to create some specific views for each content type I wonder if is it better to prepare custom newsletter manually (without Drupal interface) or is there any solution to send newsletter via Drupal interface, "easily" and automatically?
There are a plethora of newsletter generation modules in various states of support. But if you want a first class newsletter that your audience reads you almost certainly want to take the time to write and layout the newsletter in a tool meant for the job (Mailchimp's interface or a competitor).

Newsletter generators are very appealing and can be effective if you have lots of very targeted segmentation of your list. But most of the time if you are sending one news letter to the entire list they are more overhead than value.

Most of the use cases people look to a generator to support are signs of a poor communications strategies. For example: I want to send a daily newsletter about XYZ and don't have the time to write it carefully every day -- does your audience want get and read that much auto-generated mail? Or Laying out my message is too hard to get it right every time -- use a better email newsletter tool that does the job better.