Miss-trades do happen on ECNs as well, that isn't anything Oanda specific, although Oanda undoubtedly has it happen much more often. Important is how the situation gets handled. Downtimes aren't anything Oanda-specific as well, i.e. even EBS had an outage ~10 days ago for 1+ hours. ECNs do have their advantages, but they aren't the land of milk and honey some people make them out to be either.
Which ECN? IB & MBT are typically <1 quite often (before commissions). Oanda vs the ECNs in the majors is a draw, they're all very close, differences really come into play in the crosses/exotics. Oanda/IB/MBT
EURUSD on IB trades during Europe open between around 1-2 pips wide, as well as right now as I speak.
their fx trading platform were down for hours at times for a number of days during the pre-london close till new york close caveat emptor !