whatsmeow is built and maintained by Beeper's bridge architect, Tulir Asokan, and is used by many Beeper users every day with no issues. It's at the core of our WhatsApp bridge: https://github.com/mautrix/whatsapp

Baileys is also a great library with a big community and one of the primary maintainers of that is also helping us with the bridge/whatsmeow. WhatsApp integration in our old app, Texts, was built with it: https://github.com/textshq/platform-whatsapp

I would recommend whatsmeow over Baileys just because we are actively involved and incentivized to keep that working perfectly, and have a lot of data points to detect any issues with it at scale.