ive had lag and pieces of convos arrive out of order before
but they arrived.
i guess YMMV.
Discussion
There are plenty of "It works fine for me folks", but I have encountered plenty of people that have had the same problems I have exxperienced, along with some that I haven't.
If it only works for some random people, then it doesn't work.
IRC doesn't have this problem. Neither does email, telnet, snail mail, telephone, nearly every instant messaging app, forums, BBS's, centralized messaging crap.
I guess you could say it competes well with fax machines and text messaging? Whoopty doo.
SimpleX works good but not for normies, it's still early, and needs to be flushed out more but I think it is improving more over time.
Signal is the best tool for normies until then.
Threema is a close second.