After asking about the preferred subsector in the Spinward Marches on facebook and on CotI we can see what the online community think. From the results I have created a color coded chart for popularity. More green is more popular.

Here we can see that the most popular subsectors are District 268 and Regina.
The reason for District 268 seems to be that it has lots of independent backwater worlds, that are great for adventure, and are close to the Imperium and the Sword Words so that there also can be some interstellar diplomatic intrigues.
For Regina, a good reason is that the players and referees feel at home here. A lot has been published for this subsector. The first adventure (The Kinunir) started here.
Another slightly less popular subsector is the Sword Worlds. Who does not like this subsector, partly borrowed from H. Beam Piper? Rhylanor and Jewell are also popular. Probably since these are close to Regina, and also have published adventures within them.
The least popular subsectors are Lanth, Lunion and Mora. Lanth is quite divided. Its worlds more feels like they are part of Rhylanor, Vilis and Regina subsectors. Lunion and Mora are quite ordinary, and does not really have the interesting features that the popular subsectors have.
What lessons can we learn from this (if we want to create an interesting subsector)?
- There should be some backwater independent worlds.
- There should be 2 or more interstellar states quite close.
- There should be obvious adventures.
- There should be a place that can feel as home.