I used the IB datafeed through QuoteTracker. I used to have an Ameritrade account, and I used that for QuoteTracker, still trading with IB. The data from Ameritrade was noticeably better. I trade some thinner stocks, and lags to updates in volume and recent activity for some reason seems to be really obvious using IB data. There also seems to be more glitches or hang ups.
This does seem like a common complaint. I know I've seen it mentioned here on ET often. It does seem like something IB could improve on. I don't mind it so much because I'm more of a swing trader, and pennies shouldn't make a difference. But I'm not that good yet, so I too, wish the IB data feed and quotes were better. (Twice today I had an order at market, even below by a penny, not get filled.)
André