NKT may be ok for folks early in their spiritual exploration...because of its many centers mostly.
However, NKT focuses too much on self 'happiness' as defined and marketed by NKT, effectively encouraging ego development. Ego development, particularly NKT's brand of it marketed as Buddhism, will always be a disappointment, cause negativity, produce anger and harm others.
Ego development is a waste of time, effort and potential. It feels good only for a few fleeting moments while it cultivates addictions, confusion and detours. NKT's 'most faithful' display these problems clearly.
Any group, eg NKT, which does not pursue helping others but rather sits around convincing its members that they are 'pure' ideocrats is a dead end. Spiritually empty.
A far better direction to take, the innate direction of real spirituality, is to help others, worrying about oneself as little as possible. Much more will be accomplished this way, amalgamating vastly more happiness that focusing on oneself.
A pleasant 'side effect' is happiness for the practitioner of kindness...nice, though too easily becoming a futile egoistic pursuit and thus not to be dwelled upon or pursued. Nurturing others gives all of us a better future. Nurturing yourself benefits at most only one, and too easily devolves into short-term ego rewards, which distract from the most beneficial path.
As you know without thinking about it, nurturing your children, family, friends and those you do not know will contribute more than nurturing yourself. Seeing the results of your nurturing will give you many sublime insights and proof that helping others is the way to go.
The meaning of life is what we pass onto others, not what they pass onto us.