I've got some insider information about Antifa from multiple countries, including Sweden, UK, and Australia. I've also learned about the ones in the US.
They're paid, but the punk rocker thugs are at the bottom of the totem pole. They're paid either with anonymous checks, drugs, or concert tickets. They have loose or indirect associations with drug cartels, usually being frontmen during music gigs. I.E. selling drugs disguised as ticket promoters.
In the SF Bay Area on their leisure days, you can find them at lots of bars that typically host venues, such as Vool's, Ramen, DNA Lounge, Beer Revolution, Slims, Zeitgeist, and sometimes, but not often, Red House. Usually, you'll find them trying to sell drugs, which they also peddle to minors such as 15. There are numerous cases of statutory rape as well, Antifa being the older predator. There was one member who had over 700 counts of sexual encounters with minors, approximately 730.
Antifa, when it comes to danger levels, varies on the person's age and what their rank is. You have weak SJW types who are just in it for the boredom and petty side cash, and then you have the older ones, who aren't exactly fit, are more like druggie bum fight fit. The peddlers are the ones you want to be wary of when it comes to a physical encounter. The others are just lost puppies who can be easily dissuaded from being cunts through, well, being nice, believe it or not. Something triggers their subconscious when you act polite around them, like a flashback to a nanny or a grandparent, or child abuse.
Now, there's the obvious. The constant vandalism, the assaults on innocents, the smashing of private property, disruption of events, constant threats, you name it. During the Oakland riot about 5 years ago, Antifa were present, but Americans weren't too familiar with them at the time. There are quotes from Antifa members stating that they joined said riot purely for fun, as they think playing cat-and-mouse with police is entertaining