As much as I've been ragging on Google of late, I'm pretty impressed with Google Duo. Some relatives in Germany got me to start using it recently and it is smooth and intuitive.
I haven't used other video calling apps* because they all require more bandwidth than the crappy 5/1mb that I have. Duo sails right through it, and for when my wireless gets crappy, the 4G out here usually gives me a minimum of 5/5mb, so I can always switch to that and just eat data if necessary.
It is also a great solution for Android to Apple calls. My nephew in law has an iPhone, and ihave been using it with him to videochat with my grand niece. He says he likes it better than facetime or whatever the Apple app is.
Anyways, recommended.
*Also haven't used video apps just from being a curmudgeon, but it's kinda fun now to see the relatives in Krautland when I talk to them, and a blast with my grand niece.