Isn't the equation always volume dependent? For a small trader who does a couple of hundred contracts a month setting up with IB and throwing Ninja into the mix with a Kinetick feed ($110 or less per month total) works just fine. To me, even if you leave $20 or so a month on the table, the financial stability that IB offers makes it worth that and more. The real failing (and yet part of its strength) is just how damn conservative IB is on futures' margin. While I keep my highest balances at IB I also maintain two other relationships. At each I have less than $10,000 (amounts I would hate to lose yet amounts I could shake off if I did) which I put at some additional risk for valuable trade offs. Both of these firms give me stupendous leverage if I chose to use it and, while I never gear myself to their max, I like it to be my choice. At one of the firms i can trade using intraday margin even outside of RTH as long as Globex is open. To me that can have real value. If you are pushing 20+ contracts a day maybe it pays to shop but at 10 or less daily IB is a pretty fair deal and, by comparison, a very safe deal. We all take trading risk yet I, for one, have little interest in taking more counter party risk than I need to on the whole enchilada.
IB or any other futures broker don't have SIPC insurance for futures accounts. What IB and a bunch of others that have BOTH securities and futures account do is to move all excess cash to the securities account so your cash in insured. Now IB lets you customize this option, if you want to move excess cash back and forth automatically or you do it mannually. Hope this helps your issues.