Here's my response to Velocity Futures and Ninjatrader using the Trading Technologies datafeed . .
I have just opened a Velocity account with Ninjatrader. . . currently xfering accts. My contact was Dale Box (see prior posts), and thus far I have been extremely pleased by his quick responses and professionalism.
Recently, I have been running live Tradestation, Zenfire/NT, and Velocity/TT/NT with side-by-side feeds on two indentical computers (Quads with 12mb cable). Here are my findings:
Speed: All bars print at almost the exact same time . . no real difference. One might be a millisecond ahead from time-to-time but none stand above the others on a visual basis. Sim trades were virtually the same across platforms.
Time/minute charts: There was no difference among the three data feeds . . various time/price charts all looked exactly the same. Indicators tested are close to identical for TS and TT (even printing same values) while indicators on Zenfire were a little bit different but only very, very slightly and only if you looked at the values.
Tick charts: This was a very noticeable difference. All differed quite a bit but TS and Zenfire were the closest espcially on price bars. Obviously, each vendor compiles their tick charts individually. Price bars were very different for TT using ticks . . reminded me of IB where ticks are not counted unless changed. Consequently, less price bars for TT than the other two. . . thus, Velocity/TT indicators were sometimes significantly different.
Bottom line was that if you trade ticks charts . . do your homework and compare feeds. If you trade time charts . . no real problem. I don't use volume charts so no comment.
I have no affiliation with Velocity and have been a customer of Tradestation for about five years but they've become too unreliable and expensive for my tastes. My switch to Velocity was based on reputation and comm costs . . both I thought were top notch and very competitive. Also I preferred the NT Chart Trader to the Matrix.
I'd recommend Velocity but then I haven't done any live trades yet so my recommendation is limited. That's my two cents . . hope it was helpful.