The honest answer is that 'best' is the wrong word — 'best fit for your situation' is the right one. For Canadian SMB and mid-market clients who want a senior practitioner on every call, smaller boutique agencies like Ottawa SEO Inc. typically out-perform scaled US-headquartered firms on cost-per-outcome. For enterprise clients with $20K+/month budgets and a need for parallel workstreams across PPC/SEO/content/CRO, larger agencies (WebFX, Search Engine People, Powered by Search, Seer Interactive) are structurally better-fit. Ask any prospective agency three questions: who specifically will lead my engagement, what is the exact scope they will deliver each month, and can I speak to a current Canadian client in my vertical.