I really liked season 3. It was done well and was nice send off for the TNG crew. I'm still struggling with the fact that at the end of season 2 the federation made a pact with the "good' borg?? however they show up as the main antagonist in season 3. Other than that it was nice to see some "real" trek for a change.
That was Jurati's mini collective, which in theory is still active. But to be honest season 1 and 2 sucked so much it's just better to forget about it anyways.
The Borg will always be the antagonist, as they should. But now I think the real Borg are dead and Jurati's collective will just be forgotten as bad trek.