Sorry, I’ve never used one.
I understand that Tradeday and Topstep are both long-standing, reliable, honest and respected firms with very good reputations. Both open genuinely funded CME accounts for their successful traders, and that’s very easily verifiable, of course.
Topstep does that after people have got started and shown some profit, because they want to be a partner, not a counterparty. Tradeday gives its traders the choice but reserves the right to move people to a genuinely funded CME account if they look profitable, for the same reason.
So they’re both firms that are incentivized for their traders to win, not to lose like the CFD prop firms (and the CFD “brokers”).
Topstep has even won a US-government-sponsored industry award, in the past.
For myself, I’d look no further than those two firms.
But I think - as others here have often said before - that even those two probably make most of their income from the repeated fees of people trying and failing over and over again, so don’t start paying them until you know you can pass, under their rules. And read all the fine print carefully!