The best thing about meeshan's toolkit are its features to detect error in my react app which has helped alot! It also helps us identify errors before deploying our apps into production environment.
Also their support team have always listened well & done exactly what they said would be taken care off within 24 hours or less!! I like other people mentioned above but i dislike some minor things:- No live preview option- Fewer test cases available at free tier.- Test coverage not displayed properly (sometimes it displays only 20% even though there were more than 30%). Overall good product with amazing customer centric approach from them! Very impressed by this platform so far!! You should try using them once if you need something serious then go ahead otherwise stick to open source options like Jest/Enzyme etc.. We use Mesehcan to ensure quality across all stages of.