1) I did a pretty basic test and whatever's going on, it's not good enough. I sat Zorro next to MT4 and just watched the quotes. Zorro at times sat still for several hundred milliseconds while I watched MT4 tick over repeatedly.

2) No, it's a minimum delay. Per http://zorro-trader.com/manual/en/tick.htm:

Quote:
The minimum time between two tick calls can be set up with TickTime. If a new quote arrives earlier, it is delayed until the TickTime is over.


3) Sure but if I'm writing extensive logic outside Zorro, there's little point using Zorro. Broker arbitrage doesn't require a whole lot of complex logic.

4) Theoretically, if a broker is STP and using the same LPs, yes, this is true. However I think brokers do a lot of order matching between their own clients, so it's not entirely STP.

I've already been recording FIX data across a few brokers and there are definitely opportunities there. These brokers are too small for the folks with serious resources like FPGAs and ASICs to deal with.