Match the tool to the channel format before comparing avatar libraries. HeyGen is the strongest all-round pick if you want a realistic presenter workflow, but Captions is a better fit for Shorts-first creators who edit on mobile.
Do the credit maths before committing to a long-form schedule. HeyGen starts at $29/month with 600 credits on Creator, but higher-end avatar models and translation can burn credits faster than simple talking-head renders.
Treat Synthesia as the professional education pick, not the viral Shorts pick. Its Starter plan starts at $29/month with 10 minutes per month, which suits structured explainers but can feel tight for frequent publishing.
Use free plans to test lip-sync, pacing and audience reaction, not to build a full channel. Vidnoz is useful for budget testing, but its paid pricing and credit details should be checked carefully before purchase.
Keep YouTube policy in the workflow. Disclose realistic synthetic content where required, and avoid mass-producing near-identical avatar videos with minimal editing or original research.
Add human work around the avatar. Original scripting, fact-checking, custom visuals, captions, thumbnails and retention review matter more than the presenter layer.