Indeed, Telegram is the best messaging app at the moment on merit. (Especially good for business / among staff to send documents and generally replace emails which way too often doesn't reach its destination due to spamfilter issues.)
I have a large and steadily increasing contact list already, with a lot of people joining lately due Neighbourhood watches moving to Telegram due to Whatsapp's user channel limit restriction. Have personally moved loads of people to Telegram from 3 years ago when I started using it, but only over the last 8 months or so have I noticed more and more people join after hearing from it elsewhere.