>>smiche+(OP)
Also lacks proper fast and memory efficient desktop client, good cloud backups, settings for almost everything (traffic usage/space/visuals), programmable bots. And I'm not saying about some features that for example I use a lot, like "Channels" (Almost always for news, but with ability to offline access to linked websites). Anyway: you just have to test for yourself how comfortably fast their software is on both desktop/mobile platforms.
Tho sure I like Signal very much, it's just not a product for "average human" for now.