Easy to use, with great documentation! The pricing model of $0 per month makes sense as well - we are using it at work internally so there's no external cost (aside from our own IT budget). We really appreciate how easy this service has made communication between people in different timezones easier than before when working remotely or across multiple offices/cities; especially having all communications encrypted by default was an excellent addition too! Honestly I think that they could have released some more services like webhooks etc which would be helpful but other then that their whole product line seems very good overall. No major downsides yet though. Currently trying out integrations into Slack & Zapier. Really enjoying these 2 apps thus far. Trying implementing them both together within one tool where you can see what messages were sent via text message vs email / slack notification ect.