I wasn't really implying that whatsapp is in any way better. I personally enjoy using Telegram. I just expressed my frustration, because I'd really like to have only one app in my phone with all the contacts in it instead of 3 or 4.
Same for me. I want end-to-end-encryption by default, bot integration and all people in one place. Would even pay monthly for that.
Since we're talking personal experience, Signal has never had an outage (that I was aware of).
Group chats have been quite unreliable at times, although probably not due to outages, but bugs.
In my experience, signal doesn't have reliable push notifications and sometimes takes a while to deliver group messages. Sometimes my friends send me messages on WhatsApp asking me to check Signal and the message hasn't arrived yet. I do prefer signal though because there is less chance that one of my contacts has backed up our conversation to Google Drive.