Ottawa's four downtown network alternatives

The following are the city-presented .PDF files with maps as well as pros and cons of all four of the transit alternatives. Linked from the Ottawa Business Journal:

1. Bus-based Tunnel (and O-Train)
2. Bus-Light Rail Tunnel (and N-S LRT)
3. Light-Rail Tunnel (and O-Train; E-W LRT)
4. Light-Rail Tunnel (and E-W; N-S LRT)

Based on a preliminary examination, my preference would be Option Four. Although the construction period would give us a lot of headaches during construction, I think giving priority to light-rail as much as possible--from Baseline to Blair, from Bayview through the airport to Bowesville, and the rail-only tunnel--are the best options for Ottawa's long-term transit needs.

The costs, however, are nothing to scoff at. It's the second-most expensive option (Option One is cheapest at $3.16B, then Option Three at $3.37B, then Four at $3.82M, then Two at $3.87), but it also has the lowest operating costs once constructed and the lowest long-term environmental costs.

EDIT: Option Four is also the most in line with the report from the Task Force on Transportation, keeping in mind the following statement:

Canada’s capital city deserves a transit system that is enjoyable to ride, accessible, efficient, environmentally sound and developed in accordance with the principles of smart growth. Ottawa’s bus rapid transit (BRT) system has served the city well, but demand from current and anticipated growth requires more focus on light rail solutions.