When it comes to the USA, I've come across bigger and more serious busts regarding the Outlaws than the Hells Angels tbh.
Even in that fairly recent Indiana bust with Frank Wheeler, the crimes were reasonably diversified: narcotics, extortion, gambling, fraud, fencing...
During that "Cocaine Cowboy" era the Outlaws were moving tons and tons of dope from Central Florida and all over the South. Under Taco Bowman they must've made lots of money as well.
Could the area they operate in have something to do with this? In the USA the Outlaws seem to hold quite a bit of sway in the somewhat poorer and more rural parts of the South and the Midwest. Whereas the Hells Angels in the USA are based in the, by now, slightly more cosmopolitan parts where there might be less of a "gunslinger" thinking going on.
In terms of OMCG stuff I haven't come across more insane stories anywhere than those of the Hells Angels in Quebec (especially from the 70's to the 90's) or those of the Outlaws in the South during the 80's and 90's. Sure you can find biker stuff that's happening in other parts of the world, but rarely upper tier criminal activities coupled with violence on that scale.
The USA being birthplace of the 1% Clubs will have more competition & more independent clubs. It's quite geographically as well; H.A started in the West therefore majority of their membership and/or influence is in that region, Outlaws is to the Midwest, Bandidos is to the South, & Pagans the East Coast. Now there's overlapping of course but I'm speaking in general membership base. I've never seen a H.A in my state.
Hells Angels was largest at some point in the past but the Outlaws or Bandidos been the largest since the 90s in the States. Violence still goes on but it seems to be certain chapters.
The Black/Mixed 1% Clubs are the least talked about despite being just as large as any of the " Big 4/5 Clubs" and highly based in metropolitan cities. So far only the Wheels Of Soul been hit with Rico Act. The info from that case shed groundbreaking light on their size, activities, & rivalry ( which possibly still ongoing). The WOS is around half the membership of the H.A.
