Though other organizations have their benefits, due to its sheer popularity, UFC has always been the main choice for fighters. The belief is that both the best and most popular fighters are there, so it’s incredibly hard to be considered one of the greats while fighting somewhere else. Even though Bellator boasts its own stars and elite fighters, many of them (Gegard Mousasi, Cris Cyborg, Ryan Bader) are former UFC fighters, which only speaks to the organization’s power. Even when Bellator has its own fighter who becomes a champion, like Douglas Lima, a conversation about them being the best in the world doesn’t happen without seeing how they’d match up with UFC’s champion in the same weight class, think Kamaru Usman. This has always been Bellator’s main downfall from fans.
To put things in perspective, if you look at a list of the most bought MMA PPVs ever, UFC holds the first 180+ spots on its own, before any other organization makes an appearance. Bellator’s highest-selling PPV was Bellator 120 in 2014 when King Mo fought Rampage, which did 100k buys. UFC’s highest-selling event is Khabib vs. Conor, which did 2.4 million.
In terms of functioning differences, there are a few. For one, Bellator uses a circular cage as opposed to the UFC’s famous octagon, which is arguably a better format for fighting. Fighter’s walkouts are emphasized more in Bellator too, with competitors getting their own entrance videos as they walk down a ramp on their own, making the occasion feel more momentous. Coker’s promotion also does not utilize any kind of ranking system, other than there being a champion in each weight class. At any given moment, UFC has a champion, fifteen ranked contenders, and fighters who want placement in the division’s list of top contenders. Bellator’s lack of this has its own benefits and drawbacks. On one hand, it feeds into their perception as a second-rank organization and arguably takes them out of high-level MMA conversations. But on the other hand, it helps them avoid the problems UFC faces like fans appealing after Conor McGregor skips a bunch of contenders to get a title fight due to his stardom.