The products as such are very good and easy to use. The documentation is very well written and easy to understand.
PowerAdmin makes dealing with the Joomla Backend so much easier.
In making my content responsive and show nice on smartphones, I needed some help. Without any discussion the people of JoomlaShine helped free of charge, although the help subject (my content) was not at all part of their product.
Answers to questions and help/support were each time given within 24 hours.
Great people, thanks a lot.
Install: very easy, very straight forward
Import of Letterman mail addresses: perfect, no problems at all.
There might be the option: 'assign all/some lists'.
I'll make some queries and do it my selve. :)
On the "list" screen you will see a button "subscriber users" which enables you to subscribe users to your lists based on some criteria.
That way you can easily subscribe all your users to one or several lists, no need to create yourself the queries! ;)