I wonder which material for the fermentation vessel would be optimal in conducting the heat/cold from the air in the hacked fridge to the wort. I reckon glass has a very high heat capacity, increasing the time it takes to get the wort to the desired temperature compared to plastic. On the other hand it can act as a buffer, maintaining the wort longer on a more constant level irregardless of the surrounding temperature.
My main reason for using better bottles is that I have seen to many photos of broken carboys in a pool of blood. I do not trust myself with glass.
Like everything else brewing, stainless steel!
Yes glass fermenters are dangerous when slippery wet. Stainless steel isn’t translucent. Better bottles might be the best option!
I worry about plastic. Not so much the chemicals, but the off flavours. But, broken glass is a bigger concern. I’m not worried about it since I usually keep my carboys wrapped or in crates.
To answer your question: Better Bottles will conduct your fridge temp better, which could be more consistent if you are ok with faster on/off cycling. The slightly more insulative glass (plus whatever you are wrapping it in) has a bigger benefit the less active you are about keeping optimal temperature in the environment