Installation was fairly easy, although I found the server options a bit over-complicated, and it worked first time. It took a while to find all the appropriate settings, but the process was fairly painless.
I can see one major problem--the lack of full integration with the Joomla user list. Subscription seems to default to the user's registered email, but this can be changed at subscription time. If the user subsequently changes email address, this does not update Mailster's address, and they get out of sync. Finally, removing a user does not remove it from the mailing list.
Otherwise, this is a very good extension, and I would recommend it for simplicity of operation.
Thank you for your review!
We fixed the user synchronization issues in the 0.3.8 release.
In case you come across any other problems do not hesitate to contact us.