Digital banks are all the rage, and these are two of the best.Nu Holdings (NU 0.68%) and SoFi Technologies (SOFI 1.00%) are two of my favorite stocks. They're both impressive all-digital banks, though they differ in some features and serve customers in different regions. But when compared head to head as investments, which one wins?  The case for Nu: Unbeatable opportunitiesNu is based in Brazil, its primary market, and also serves customers in Mexico and Colombia. Brazil's financial sector was historically ...