It depends

One of my favorite quotes is the following:

"The fundamental delusion — there is something (or someone) out there that will make me happy and fulfilled forever.”

This delusion is the search for utopia - in a system, a person, an institution, a movement that solves your problems and quells your insatiability, forever.

In relationships, people tend to aspire for common personality traits in their partners: kindness, intelligence, conscientiousness, positivity.

Still, a frustrating fact that anyone who has been in relationships has discovered: the personality traits that yesterday made your beloved shimmer, today make you shudder.

Perhaps you're in a sullen or reflective mood.  You feel a deep desire to bear your soul and connect emotionally or intellectually.  

The traits you most want in a partner are sensitivity, a calm temperament, and an aptitude for listening.  The expression of these qualities is a balm that heals.

A few days later, you feel light and radiant.  You yearn to bask in the sunshine and excitement of being alive.  

The qualities you most want in your significant other are peppiness, light-heartedness, a propensity for unbridled affection.

Two different mind-states - two different personality propensities, rarely found in the same individual.

Long-term, which qualities are better for you?

The most common and accurate of answers applies: it depends.

This may be the simplest explanation for a trite observation about relationships: they take work.  

One person is unlikely to be able to provide for your needs in all circumstances.  If they can the majority of the time, this might be correctly labeled a successful relationship.