Benjamin Moore is what most Ottawa painters reach for on interior work — Aura, Regal Select and Advance (for cabinets) flow beautifully, hide in two coats, and the color library is the industry reference.
Sherwin-Williams Emerald and Duration excel on exteriors — they handle Ottawa's freeze-thaw cycle, UV exposure and humidity swings extremely well. Cashmere is a strong interior wall paint at a lower price point.
Practical advice: pick the line, not just the brand. Builder-grade paint from either brand (BM Ben, SW ProMar 200) is fine for rentals but won't perform like Aura or Emerald in a long-term family home.