Today I am on Truedata's velocity 7 day free trial. This is what my experience so far.
1. Data updates with a lag. LTT on my NOW terminal shows many change/blink of price but Truedata is catching upto them with a delay. Few changes are never being caught and price on my Amibroker stays as it is. For eg - price on Ami was 7850.3 and on terminal it was 7850.3. Terminal changes through 50.8 - 50.5 - 50.3 - 50.1 - 50.3. But on Ami, it still shows 50.3 only. Then on terminal price drops to 7848, Ami stays at 50.3 for 3 more seconds. Then on Ami price drops to 48.7, At that time terminal shows 47.15..
My net connection is fine. Checked the feed with 2G and 3G. On 2G truedata lags more. GFDL was working same in both 2G/3G. Latency was very less in case of GFDL.
2. Compared few candle's OHLC from NOW's hourly statistic OHLC. On few candle's High/low are showing wrongly. Even after a force backfil from Velocity candles are not showing correct data. Lets see if at EOD they update it and change the candle.
3. Trudata's customer care urges to turn off firewall, keep the User account control setting to Low and also turn of antivirus. GFDL feed was working fine with firewal turned on, account control setting at High and Antivirus ON.. This is the major drawback I feel..
So far these two issues are quite serious for me, and I think I wont wait for 7 days of trial to complete. Thnking of re-subscribing to GFDL tomorrow itself. Still will wait for tonight.