The
ACEM International organisation promotes mantra meditation. They claim that (their) mantra meditation technique leads to relaxation faster than "other" forms of (concentration) meditation. What I have seen in my personal ACEM experience is that they are genuine people who focus on their method, but don't have so much focus on "enligthenment".
They stress (haha!) that you should take on your mantra calmly when you have lost it.