absolutely not true, sccz. I sat and watched a stop order (not a stop limit order) be ignored and ignored and ignored as the price went up and down and around it, in slow trading at 2am, in USDJPY where there was plenty of liquidity. I have also watched limit orders be acknowledged and then not registering in the market depth and similarly being ignored as the price repeatedly hit it and then dropped below and then hit it again. I have complained about each of these problems to IB; in the first case I got the answer that Citibank wasn't accepting IB's orders "for some reason" and in the second case they pleaded a software glitch. And I have already complained about orders not being acknowledged for minutes on end, and losing a bundle as a result; or being stuck for the weekend with a position I wanted to close out because my order wasn't acknowledged though it was submitted several minutes before closing. Trading promised that they would investigate and e-mail me back on some of these issues, but it's been a week or more and I haven't heard a peep. Of course the chances that they will reimburse me for the money I lost are zilch. There are still reasons why I stick with them: I spent a lot of time developing an API for TWS, and at least they're not crooks. But they like to throw the word "professional" around a lot, and that's one thing they ain't.
I have observed the above in my limited experience also- and agree with gspaulsson. Besides, if the price gaps past your "limit" order, and doesn't fill, it becomes a market order at that time, and you "should" be getting the better price (sometimes I do, tho usually I get my limit price).
No apparently you just haven't had this problem. It's real, the IB staff doesn't acknowledge it is there but when you have a limit bid on the system and the ask trades 3 pips down through your price and you get no fill, you do the math. Their response is "Call tech support when this happens". On hold, 20 mins later tech support price isn't through my bid and they do nothing.
Yes I agree with every word of this and have had virtually identical experiences on all counts. Orders not showing up in market depth, price trade throughs and no fills, quotes ghosting several pips off the market just as my order is placed, complaints and no cigar - no take that back I think they did rebate $40 (split the difference) one time but ignored a couple over $400. The problems seem so far out that they are hard to believe but after experiencing them on IdealPro I realize that it just isn't ready for prime time. I too am still an IB customer. Globex fills on futures are quick and flawless. IB has quick quotes.