Just as an FYI - both Canada 3000, and Skyservice are licensed, and approved by the FAA to operate these a/c into, out of, or base them within the U.S.A. (as both have done). In order to qualify for this, they must meet FAA standards with respect to safety. In many instances, these standards exceed FAA requirements.
As an example, with respect to crewing, the FAA allows U.S. airlines to operate with 1 Flight Attendant per 50 passengers, while elsewhere (including Canada) the requirement is a more stringent 1 Flight Attendant per 40 seats. So in that instance, if you were flying on a Canadian, or British, or Danish (etc.) registered aircraft, operating for a U.S. airline, you will have additional crew to manage an emergency - not the bare minimum allowable, as you would on an FAA mandated, U.S. registered aircraft.
Although the amount of exits per seats is certainly important, overall safety is not limited to that one factor.
The regulatory authorities in many other countries are equally qualified to mandate airline safety as the FAA. Just because the company is not registered, or based in the U.S., it doesn't mean it is less safe.
Having said all that, having flown Airtours, Air2000 & Leisure - either 174 or 180 seats are too many for an A320 - from a comfort perspective (but still better
than 235 in a 757...)