btw not going to give you an education. But some do move you to actual live and some don't. You have not fully researched this topic in depth, please don't pretend like you have.
Why would I research this piker shit?
I am telling you that most of these places do not have a clearing firm. If I asked you who your "prop" firm is clearing you'd have to look it up.
You stated "why would I care if it's demo?" which is absurd. You threw money away on the combine to contribute to a scam biz who charges you to demo -> internalizes your orders -> keeps 100% of comms. Worse, you're receiving a split.
You could have opened an account with AMP or similar and paid low rates and received intraday $400 haircut on ES.
The money you pissed on the combine could have gone to AMP with their $40 (assumption) MES margin.