For a small team focused on manual testing without Jira, all three you listed are reasonable. Quick take: Tuskr: cheapest, clean UI, but limited integrations and reporting depth. Good if budget is the primary constraint. Qase: most polished of the three, but their free tier is restrictive and pricing climbs fast as you add users. Testiny: newer, simple, but smaller community means fewer resources when you get stuck. I'd also throw TestCollab into your evaluation (disclosure: co-founder). 14 years in market, manual testing focus is our bread and butter, no Jira required, and the free trial doesn't need a credit card. Starts at $29/user/month.

Whatever you pick, my advice after 14 years: don't pick based on features you might use someday. Pick the one your team will actually use day one.