We have used this tool for all of our projects since 2015. It is very well developed solution with great support team to assist you throughout development process. There are no cons about it when using as an API provider in any project that uses authentication mechanism such us OAuth2/OpenIDConnect Flow etc. I would recommend anyone who wants to use Authentication Mechanism like OpenId Connect /OAuth 2.0/Oauth1.4/. If they want to implement their own custom authentication flow then i do not see anything wrong with them but if its already available from other providers than why reinventing wheel? Security related issues.