"Which analytics tool should we use" is usually the wrong first question. The right first question is what you need the data to prove: marketing performance, product behavior, legal defensibility, or some mix. The tool falls out of the answer.
What actually separates the tools?
Three trade-offs do almost all of the work:
- Capability. GA4 and Matomo are full web-analytics suites with e-commerce reporting. PostHog is product analytics: what users do inside the product. Plausible and Fathom deliberately do less, in exchange for being simple and cookieless.
- Ownership. With GA4, Google processes the data and the EU legal ground still shifts underneath it. With self-hosted Matomo the data never leaves your servers. Managed EU or Swiss hosting sits in between.
- Maintenance. Free self-hosting costs your time. Managed hosting costs money. GA4 costs neither, and you pay in a different currency: complexity and dependence.
Every comparison under this hub is one pair of tools, one honest verdict, and a "who should not switch" section. No affiliate links, no scoring tables with invented decimals.
Do you even need to switch?
Often not. A broken setup migrated to a new tool is still broken, just less familiar. If your numbers feel wrong, the cheaper first move is finding out what your current setup actually does; that is a Clarity audit, and more than once it has ended with "keep GA4, fix these six things."
Switch when the tool itself is the problem: data residency requirements you cannot meet, consent losses you cannot accept, or questions (product analytics, cookieless measurement) your current tool structurally cannot answer. The comparisons below are for exactly those cases.