Ed is right. I had to switch to BMPCC with my speed booster because the low light. Also, I shoot weddings in ProRes LT so the image isn't as strong as the 2k 12 bit raw from the Bolex.
Realistically, it's a terrible camera to use practically for a wedding or doc. I think the c100 is the best wedding camera. All day battery life. Great high quality compression. Perfect skin tones.
Ed is also right about the fact that most the stuff shot on Bolex is purposely narrative. Which means more care has gone into the lighting and composition. A good DP can make any camera look good just like a good musician can make any instrument sound good. My buddy just got back from Nicaragua where he was going to shoot a doc on C300. They wouldn't let him bring his camera rig into the country so he shot an entire professional project on an iPhone and a Nikon point and shoot camera and the client was actually happy with it. Don't forget that these numbers bit rates and sensors are honestly not as important as you think. If you make a killer film using whatever and a producer sees it and hires you, you'll have budget to shoot on Alexa or whatever you want and it won't matter what sub $3,000 camera you purchased. Just get something that is the best workhorse for you and will make you happy.
To me, I prefer the look of Bolex to any RED camera. So I rent the Bolex on my higher budget stuff and I usually have tons of room left over for crew and lighting because a Bolex is super cheap to rent. Having grip and gaffers who know what they are doing is the real secret.