You’d be spending large amounts of money for incremental differences. The OKW will have higher candela for good long distance performance, but the OWL has substantially higher lumens, which benefits CQB and close range use because it creates a greater amount of light spill. If distance is the sole purpose for this light, there’s no reason to switch to the OWL and drop 19k candela. The OWL is a much more well-rounded light than the OKW, but you have to weigh your needs.
As stated, the OWL is a big bitch, and it’s a lot larger than what people realize. It’s about as big around as a toilet paper roll tube. It’s also only designed to be mounted one specific way in one specific location. In contrast, the Modlites and the Cloud REIN can me mounted in many more locations and configurations, just like the SureFire M600. You can run the light in a remote location and put the switch wherever, which is a bigger benefit that can be adapted to different rail configurations. The Modlites also have integration with SureFire switches, which is a great feature.
If you want the best of all worlds, it would make the most sense to get the Cloud Defensive REIN, and not the OWL. If you just really want the OWL, you’ll be happy with the quality of it and there’s nothing wrong.