> Durov might be sketchy and weird libertarian, but damn, his developers can deliver good and working product really fast. (And from what I understand, it's a really small team.) Credit where it's due.

The UX is great. The Telegram clients are quite nice to use. They're open-source, too. Well, 'open-source' as in they dump a huge diff into the source tree now and again, and they never interact with outside developers submitting Feature Requests and Issues.