I am on Android, and for me it used to be slow, but recently has become very fast again. I just opened the app and it took <=1 second to get to see my balance. I am on a very new phone though (oneplus6), and I don't know enough about how different hardware affects speed.

That said, since I changed some settings to reduce battery/data usage, the notifications for spending often don't turn up for several minutes, where they used to be instant (before being able to put my card back into my wallet).