According to EDUCBA.com:
After playing with PowerBI and Tableau for 2 weeks, I must admit, that tutorials for Tableau are much better than for PowerBI. Easiness of usage and publishing data to server is much simpler in Tableau. Tableau has more connectors than PowerBI. Pricing model seems to be more simple and affordable for Tableau.
And what convinced me, was that in Poland we have professional company: ASTRAFOX, which gives lots of free webinars and professional support for Tableau and Bussiness Intelligence:https://astrafox.pl/