Totally agree. The "serious trading" was meant to be something along the HFT lines, but then it turns out that neither of these feeds would be even remotely good for that. I originallly promised a report on latencies, and, unfortunately, I am still struggling with getting a working timekeeping card (had to RMA the first one I got). Yet during those few days when I had it working (with a 8 ms / hour drift), the latencies I observed were the following: During the first 2 hours after market open: IB (trades only): Range: -480 .. 1000 ms, Average: ~550 ms, Std: ~300 ms. AT trades: Range: 60-10,000 ms, Average: ~450 ms, Std: ~550 ms AT quotes: Range: 35-10,000 ms, Average: ~300 ms, Std: 600 ms (My local processing delay is less than 2 ms per tick). These numbers are for a dozen or so of mid-liquid (~$50M daily volume) stocks from both NASDAQ and NYSE (those just happened to match my trading filter for a particular day). Notice the negative number on IB timestamps. Makes one wonder what the IB timestamps really are and at what point they get stamped. The average is very close between IB and AT, IB being a 100 ms slower than AT trades, the latter being another 150 ms slower commpared to AT quotes. Still, AT has a wider deviation, though AT timestamps are probably more "real" than those of IB. But for both of them one can forget about any sub-100 ms trading or even sub-500 ms trading. Starting with 300-500 ms quote latency and addding another 100-200 ms of order handling brings it to a 1 second timeframe - must be an eternity in the world of HFT.