Maybe not important for everyone, but tambur supports SSL for all pricing plans.

As pusher we are big fans of WebSockets, afaik pubnub uses some sort of long-polling for their message-handling. I am not sure if pubnub provides a way to trigger presence events. Pusher also provides these features afaik by using separate channels for e.g. presence events (not sure though). In Tambur you enable presence-events, direct- and authenticated messages on the same channel (we call them streams). So we probably have more in common with pusher than with pubnub feature-wise, we just do things a little bit differently.

SSL is certainly important for a lot of apps handling sensitive data (as well as AES: http://blog.pubnub.com/pubnub-adds-cross-platform-aes-symmet...). It of course has to (and does) work seamlessly with PubNub Channel Presence, Message History and other features of the real-time messaging infrastructure. The key to providing an affordable pay-as-you-go pricing plan is scale, whereby fixed costs of the globally-deployed messaging infrastructure are amortized across thousands of apps, millions of concurrent users and billions of sent and received messages: http://finance.yahoo.com/news/pubnub-cloud-exceeds-1-million.... More info available at help.pubnub.com FAQs.