I am implementing an instant messaging system that is completely dependent on websocket. Since the network is developing quite fast, and websocket is in the web standard, I decided to use flash websocket backup for any browser that does not support it by default (Firefox, Opera). Here is what you may know:
I am using websocket. I use a clean website server . I do not use any other protocols. I do not use socket.io. I have to say that if you decide to use only websocket, you won’t have the benefit of socket.io lib, even during development time. This adds extra overhead to your server due to the support of several transport layers.
On the client side, I use a websocket + flash version of websocket backback , which implements websocket specifications using a flash socket, and I would say that there is no noticeable difference. The only thing you need to know is because of the “same origin policy”, you may need to query the flash socket policy on your own (by default on port 843) in order to allow the flash socket.
We are currently using a private server because we have a dedicated system administrator. However, it is better if you can focus on what you intended to do, rather than on unwanted things. Oh, and sometimes, it's better if you have full control over your own server :-).
Hope this helps.