Bid/ask stop triggers are far, far superior to last price triggers, IMO; however, I haven't seen many software platforms which offer it. IB offers it through TWS, and it's available with XTrader via a third-party app for MD Trader.
Bid/ask triggers are especially good for markets with a lot of noise, a wide bid/ask spread, or ones that can creep considerably past your trigger price without a trade going off (e.g., natural gas, silver, RBOB).
I wish NinjaTrader would offer them.
