I currently use IB for futures. But I do not like its still expensive future commissions. For the last corn futures, I paid like $2.40 one side. I'm fine with its high margin. Do not trade futures very frequently. Maybe fewer than 10 contracts a week. No micro contracts. Mainly energy (CL) and agriculture (ZC, ZS) contracts. I also have E*Trade, Schwab Fidelity and TD Ameritrade accounts. I have not used them for futures. Just some extra cash to keep accounts open.
At that volume you are most likely not going to find a better rate. I have been looking at Tradovate through Dorman and if you lease their platform you can get better rates, but it wouldn't work out at your level of volume. Same for Advantage, they can go lower, but they need more volume. Maybe someone else has something, but make sure you are looking at a reliable and safe firm.
Actually mainly looking for secondary futures broker. Used to have the regular IB full account, but has changed to the Lite account. More ETF based now. So do not really need sophisticated platform and speed etc. Yes, the first thing traditional futures broker asked was the trading the volume. I get futures trading set up on all TD, Schwab and E*Trade. But have not done anything there. I may look into Schwab StreetEdge to see how much it charges.
I use Schwab as my backup for futures. I believe they are $2.25 a side for futures. the platform is very basic.
AMP is pretty much the least-expensive futures broker you'll find out there. Check their pricing. Combine them with their free MT5 offering (for unsophisticated platform as you say) and it's a good deal.
$2.4 per side for All in cost (exchange fee + order routing + broker commission) is not bad. The largest portion of this cost is from the exchange fee. The exchange fee is $1.97, so you are paying $0.43 for order routing + IB commission. Only way to pay less would be to buy exchange membership, but at your monthly volume the savings per contract would not offset the monthly membership fee. For reference, here is NinjaTrader's commission on Corn Futures (https://ninjatrader.com/PDF/ninjatrader_futures_commissions.pdf) You can also see the AMP commissions here: https://portal.ampclearing.com/account/commissionquote.aspx