I use hybrid in vim and base16 in everything else and that's about the best I've found so far. The base16 "builder" seems like it supports the most things:
Telegram bills itself as secure, which comes with a rather large burden of proof if anyone is to take you seriously.
As the saying goes: "don't roll your own crypto, unless you're a professional cryptographer, and even then…". Telegram are not cryptographers but decided to roll their own anyway and have come in for not a little flack as a result.
Search for "telegram app crypto criticism" and you'll find plenty of examples of this.
Is Telegram secure? I'm not qualified to answer that, but I understand enough to be sceptical.
> On a related note, is there any multi network app that supports video?
Yes, both Pidgin and Empathy support voice and video calling via XMPP. I suspect you'd need to use a "standard" XMPP server though - it wouldn't work over gtalk or facebook chat for instance.
You're probably already aware of this, but just in case: it's possible to force Swing (and AWT) apps to use the system's font rendering with the "swing.aatext" and "awt.useSystemAAFontSettings" respectively.
https://github.com/chriskempson/base16-builder