I haven't tried Signal on a budget grade Android phone though. I have a few Galaxy S4s I use for various odd projects, but most "modern" apps run fairly badly on those.
I'm also "looking forward" to a weekend or two's worth of frustration failing to get Signal for Linux desktop running on my PinePhone when it arrives... ;-)
And all that with most features of Whatsapp missing(on my last test). Currently I don't see a reason to go from Whatsapp to Signal. Encryption is the same and Moxie see's the Signal-Network as his own where no other client has to connect. So the trust in him is better than in Facebook, but not as good as it could be.
https://faq.whatsapp.com/general/download-and-installation/a...
What do you find "awful" about it's usability?
Whatsapp sucks for me because of an unusable desktop client. Their backups system is extremely slow. I've found that messages get sent and received slowest on whatsapp when comparing with other messaging apps even if the gap is almost inconsequential. There's a woeful lack of features that I love on telegram that make the app very barebones and dull. You cannot edit messages. The replying UX is a bit irritating. There's tons of stuff but this is a small gist