Big obvious problem with WhatsApp is that it's owned by Facebook and seeing as WhatsApp is free they're most likely using it as a data collection / tracking mec

Big obvious problem with WhatsApp is that it's owned by Facebook and seeing as WhatsApp is free they're most likely using it as a data collection / tracking mechanism. Signal is much more based around privacy, it's open source and Open Whisper Systems are funded more transparently through grants and donations. But ignoring that and just looking at the features. Typically I use them for different things. WhatsApp works better for sharing with groups of people because lots of people have it on their phone. I use Signal as a layer on top of SMS but typically only 1-1 communication, so if both of us have Signal then great, but otherwise it's just regular SMS.