To find a good instance you need to look for certain things:
- Do they have limits on how many users can join the instance?
(This is in force to keep the mod to report ratio healthy).
- Do they have a dedicated team of mods? Who are they?
- Read their 'About' & 'Limited Servers' sections. Who are they blocking? What are they blocking for?
- How active is the instance? Despite being invite only or limiting registrations temporarily, is there a lot of activity?