Quote from osorico:
Not sure about the "best", but I will tell you the RCG feed is quite stable with very little lag. But the RCG platforms suck, imo. Additionally, RCG does not allow 3rd party to access it's PATS feed, so you're stuck using their sucky platforms, usually rebranded JTrader or Onyx.
fwiw; OpenECry used to have a PATS feed. Even QT integration with it. You had to specifically request it. I Don't know if this is true anymore. I'll ask.
RCG does allow Ninja Trader for their Pats feed.
Best regards
Saico