Today I'd consider going with a service, but first I'd see how https://github.com/LearnBoost/websocket.io looks. Most of our problems have been with abstractions in the socket.io client and scaling issues with server process chatter. The chatter shouldn't be necessary with websockets-only.

With https://github.com/LearnBoost/engine.io the abstractions are greatly simplified, which is what I'm announcing today.

The socket.io codebase has been shrunk dramatically, and it's as a result easier to scale/maintain.

That's great!