In terms of UX I beg to differ. Everyone I've been in contact with likes WhatsApp because it's sort of "iMessage for Android" or "Skype, only less worse" and use it mostly because their contacts are using it. The moment they have enough contacts on Telegram they just don't look back and find it a much more pleasant experience.

But it shares all the metadata with Facebook which sucks. Threema and Signal are better in that respect and you loose almost no features.

It shares your full _contacts_ with Facebook.

This doesn't just "suck", it's completely unacceptable.

While bad I think it's worse that the location available through your IP is available to facebook. Further they can guess with which contacts you work with, are good or not so good friends with. And it will be kept forever at Facebook and at companies like Cambridge Analytica.

How do you think Telegram plans to monetize? I realize they had an ICO that raised $850M, but that is not a sustainable revenue mechanism in and of itself.

Until you try to install it on your tablet and finding out you can't use it there.