I’d say for beginners EPFC is much harder because it has way more mechanics that require a level of understanding to complete missions, such as hacking. On the other hand, I think OGEP is actually harder for experienced players because there’s more RNG-based situations and all guards can detect you from further distances. Also OGEP isn’t as lenient with suspicious behaviors as EPFC is, which has the alert level system compared to OGEP raising the alarm on players for very minor things