Regarding fees, refer to the footnotes on the "additional fees" popup on this page...
https://www.generictrade.com/commissions/
*Generic Trade clients will automatically subscribe to the Generic Trader suite of platforms (Generic Trader Professional, Online and Mobile) and will be subject to a $59/month subscription fee. Since the CME Group has raised their fees (see above for details), CME Group and ICE fees will be added by request only. If you wish to select the free Generic Trader Online exclusively, you must do so by email, prior to the initial funding of the account.
Regarding your mention of no data fee, a.k.a free data, refer to this page...
https://www.generictrade.com/cme-group-data/
Please note that if you are not subscribed to the market segment, you will still receive real-time data, but only for the last trade and not for the full market depth.
The oddities I refer to are in the footnotes on this page...
https://www.generictrade.com/commissions/margins/
The thing they call Enhanced Intraday Margin System (EIMS) appears to apply to some very popular products including indexes!
¹Standard Day Trade Margin is offered to most clients with futures trading experience and is available during any open session as long as a $1000 balance is maintained. Strict adherence to the Intraday Margin Policy (provided upon funding account) is necessary to maintain day trading margin privileges.
²The Enhanced Intraday Margin System (EIMS) is available by request from seasoned traders that have familiarity with our platforms and risk management expectations. At least $1000 must be maintained at all times and clients enabled with EIMS, are only permitted to trade from 8:30am CT to 3:05pm CT. Full details and restrictions of the EIMS are outlined in the EIMS policy.
Thanks for sharing your current first-hand experience.
Good trading to you.