This post is spot on, on every point. It describes perfectly the mechanics of how we look at potential recruits and what we look for and on behalf of the person applying it is also perfect.
I would strongly emphasise on Voice, we always talk to people before deciding as it is the best way to get a feel for them, or even some times go on a roam with them to get a feel for the people.
If anyone invites you without asking for an ESI check (what used to be old API check) apart from Pandemic Horde, they are most likely a faceless blob/not very close with their members, I would suggest asking why they don’t ask for an ESI and how many people are on voice normally. Activity is one thing, activities together/as a group is another as normally the groups that are not good with this just accept anyone and everyone trying to get as many to join as possible tend to be the ones that don’t ask for it.