Personalized Mass Text tool (app)?
One nice alternative to the ones you already have is Group SMS by Tur Han available from Google Play Store.

It allows you to compose the message and:


add first and/or last name to the message text;
select the recipients individually.


Works pretty good, it's a free app (small publicity banner), with no bugs on my end. Shows the progress of each message being sent.



If you go to the PRO version, things just keep getting better and better:


  
  create groups of contacts for quick sending (friends, family, work...)
  History keeping &amp; management
  enhance search bar
  select/deselect all your contacts with 1 touch
  template management
  history track of all messages with statistics
  add Free