The short version
Headspace is curriculum-led teaching under one voice; Insight Timer is the largest free meditation library on the market. Pick on whether you want structured learning or open exploration.
When Headspace is the right pick
If you want a structured introduction to mindfulness with a clear curriculum and a consistent teaching voice, Headspace is the right shape. The Basics course is the strongest beginner path in the category; the $70/year subscription is the cost of curated polish.
When Insight Timer is the right pick
If you want the largest free meditation library on the market — access to Tara Brach, Jack Kornfield and thousands of other teachers at no cost — Insight Timer is the right shape. The free tier is genuinely free; Member Plus is optional.