IB is a good broker if you want to trade stocks, options and futures. If you only want to trade futures there are other brokers that have better commission rates for moderate volume traders.
IB's unbundled commissions start at $4.70 RT and drop at specified volume breaks.
Transact Futures charges $3.76 RT with a minimum of 274 RTs a month.
Lightspeed Trading charges $3.30 RT with no volume minimum and $65.00 a month futures data feed charge.
If you will be doing low futures volume or will have inactive months, then IB is a better choice than brokers with specified volume/fee minimums.