At the request of @Shipwreck_Jones (not sure if I should thank him, lol). As concise as possible:
In contrast with NBSI, which is the more natural set of rules of engagement in EvE’s universe, NRDS makes life a little more complicated, especially related to SOV NRDS where one is indeed depending on a level of goodwill from bigger blocs for its very existence when not implemented from a position of strength. For NRDS groups the situation is “do not fire unless fired upon”, which usually puts them at a disadvantage in pvp. The old remedy, a KOS-list holding players considered hostile because of previous infractions, is not flawless and may even be unfair in the long run (see provi’s history).
There isn’t really a PRO anymore, especially now that the large blocs have their own recruitment programs and corporations for (very) fresh pilots, offering better protection against invasion and aggression in general, while the old PRO argument was that it constituted a low barrier for nullsec (or wh) life. The only tiny PRO argument left with SOV NRDS is the chance to grow from neutrals who are allowed to sample nullsec PvE life.
So what’s left ? It’s a clear choice of conduct, a self-imposed limitation if you will, and that can become a group identity for like-minded people. It has the added risk of becoming labeled as an elitist group by non-NRDS groups and attract extra (negative) attention. NRDS rules by themselves do not give benefits, only the corp/alliance environment and policies can create any benefit (which is true for any corp/alli regardless of nrds/nbsi/npsi). Bottom line, it’s what you make of it, and how you make it attractive for your members, and convince them of the added risk - so something extra will be needed. An example: NRDS groups like Signal Cartel, could be shot out of existence easily, but they give a clear advantage to the EvE community in general by their rescue programs in w-space and, as far as I know, are left in relative peace. Provi bloc was an entirely different matter. See other threads. Setting your group apart from the main stream is not without extra dangers.