Most lists are just SEO fluff or vendor-sponsored. They rarely mention how the tools behave at scale or what they *actually* track.
I'll only mention tools I've either stress-tested myself or seen credible, reproducible data on from teams with >50M monthly sessions. Assume everything below is for that tier unless noted.
* **mParticle vs Segment:** mParticle's data governance is better out of the box, but their event volume pricing gets punitive. Segment's ecosystem is wider, but you're trusting their transform logic. For under 10M events/month, Segment's docs are easier.
* **Server-side Tagging:** Avoid vendor tag managers for core AEO. Use a cloud instance of GTM server-side or an open-source alternative. You control the data flow. This is non-negotiable for honest attribution.
* **Attribution:** **Never** trust a platform's self-reported attribution (Meta, Google Ads). Use a dedicated tool.
* **AppsFlyer / Adjust:** The standards. Heavyweight, expensive, but built for mobile-first, high-volume.
* **Northbeam:** Strong for social/e-commerce if you're heavy on Meta/TikTok. Their LTV modeling is more than a black box—they'll sometimes share the variables.
* **Synthetic Monitoring:** If your geo-targeting or personalization breaks, you need to know before users do. Use a synthetic checker (e.g., Catchpoint, Perfalytics) to validate location-based content serves from key CDN nodes.
* **CDP Consideration:** Ask for their exact deduplication methodology. Most can't do deterministic cross-device without a logged-in ID. Their "identity graph" is often probabilistic guesswork.
The business model (subscription vs. ad-driven) and your primary traffic source (mobile app vs. web) will dictate 80% of the choice. Everything else is just window dressing.
/skeptical
Show me the methodology.