Are the Jedi and Sith "special" compared to other similar groups?

Question

In the Star Wars saga, the Jedi and Sith are by far the most prominent light and dark side organizations, respectively. However, many other groups of Force-users existed. There are only a few canonical ones so far (The Nightsisters and the Inquisitorius springing to mind first), but there were several dozen known organizations in the Legends continuity.

Did the Jedi and Sith have a stronger or otherwise special connection to the Force, or were they exactly the same as all the other Force-using originations in the figurative eyes of the Force?

Answer 1

    Jedi and Sith were politically most active on Galactic level. Jedi intervened their Order with the fate of Republic, they traveled far and wide, discovered many secrets which in turn grew their knowledge of the Force, allowing them to become more powerful and to discover more secrets :) Sith were mirror opposite, they wanted to conquer Galaxy, but they were also explorers, not allowing themselves to be content with what they knew. Thus, both organizations acquired more knowledge then other Force sects which seem to be content with what they have. In fact, other Force groups were either splinters of Jedi/Sith that became isolated or some local traditions stagnating on their own home planets. This complacency limited their scope. Also, it is worth noting that gifted Force individuals are rare, and if organizations restricts itself to one planet, it would severely limit pool of available recruits. Granted, some species are more Force sensitive then others, but even among them true talent could not always be found in one generation.

    Out-of-universe, Lucas first created Jedi as protagonists and (arguably) Sith some time later as antagonists. There was also early concept of Whills, but they were not actualized until much later. All other organizations, both in Canon and in Legends, were essentially just a fillers for some story arcs. Therefore, they could not be as powerful as Jedi/Sith and they cannot permanently influence events on Galactic scene.

Answer 2

The Jedi Order is the greatest Force-user organisation because they act as a political/diplomatic force. By being an integrated part of a galactic political power, they have the scope and influence needed to expand both their understanding of the Force and their ranks. Being able to recruit across the whole known space is a big deal, especially considering how scarce potential Force-users are.

The Sith are the Jedi Order's shadow: the first Sith was a Jedi who rebelled against the order because he wanted to explore the dark side, something forbidden by the Jedi Order. The Sith became a faction by itself when more Jedi joined them, attracted by the dark side.

Both Jedi and Sith are curious by nature and want to develop their use of the Force. The difference is that Jedi apply a kind of Vulcan code - valuing peace over conflict and rational thinking above all - while Sith aren't afraid of either the chaos or the dark side.

Anyway, the Sith are mostly Force-users that could be Jedi if they were willing to restrain from emotional reaction in order to stay away from the dark side. In other words, any Force-user that see either emotions or the dark side (which are quite similar things in fact) as assets will become a Sith if they aren't already.

The fact that both always try to rule over the galaxy and that any Force-user trained by one side can turn to the other depending on their predispositions, they are both sides of the same coin - that coin being either the Force itelf or the current galactic order.