I have an interesting relationship with the Jak and Daxter series. I went into the first game expecting absolutely nothing, and came away so impressed that I now consider it one of my most beloved platformers of all time.
But was once a whimsical and fairly child-friendly series quickly took a dark turn, as Jak is not only captured at the beginning of the second game, but tortured for two years and turned into a half-mutant dark version of himself. Jak was no longer the cute mute he was in the first innocent adventure -- he was animated, vocal, and angry. This evolution of the formula is just one way Naughty Dog kept the franchise fresh, and relevant.
In other words, you absolutely need to experience this trilogy -- but probably not on the PlayStation Vita.