Yes, I agree. Telegram uses secured connections so avoids most of the Internet security issues you would otherwise have to deal with. It is also possibly the easiest of the secure messaging services to write bot's for. I also doesn't have the message limits that some services have. I regularly push hundreds of messages through it.
It lets you create several different types of interactions including slash commands, buttons and conversational interfaces. Audio, video and other media is also possible in both directions.
I think that there are 3 nodes that will talk to Telegram. The telegrambot one is the simplest I think. Chatbot is more complex but integrates Rivescript which is great for writing conversational interfaces. There is a separate Rivescript node that you can use with telegrambot if you like.
Red-bot = Chatbot - the author seems to use different names. The documentation has been somewhat lacking in the past as well - hopefully that has been resolved now.
The downside of it is that it adds gazillions of nodes to your palette.
