For reference, my favorite way to play is with many disconnected small and tiny clusters. And yet, I hate playing the Navigators.
My favorite is the Yor. Once the planetary Durantium was added, I no longer restart if there isn't an orange star in my sector. This isn't to say that I won't beeline for them.
With the policy manufacturing bonus, and (with enough Durantium) no limitation on population growth (there is a hidden max somewhere, but if a planet hits that point just remove cities and let it produce modules) there is pretty much no stopping them.
On top of this, not having to research Extreme Planets, and not having to worry about food at all, they get the best planets in a sector (if shared) early game.
My second favorite are the Torians. Aquatic Mastery from the start is great, but sometimes those water planets aren't around. In which case, they are optimized for combat. The fast growth rate (and policies which stem from this) help with both colonization and starbase construction. Aquatic worlds tend to be high in food, so getting those class 1 planets is no issue, so long as Crime is contained.
I'm curious to others' thoughts.