Real-time notifications: WebSockets or Server-Sent Events? That's the question.

so i'm thinking about building a real-time notification system. webSockets seem powerful for two-way chats, but server-sent events look simpler for just pushing stuff from the server to me. what have you guys seen out there? when did you pick one over the other, and what made you decide? any tricky bits or performance things i should watch out for with tons of notifications