Adafruit is pretty clearly the front-runner these days in the educational/hobbyist market, Arduino (and even SparkFun) have fallen by the wayside. My only gripe is the focus on micropython these days, it can introduce a barrier later in the learning process when you eventually need to leave the nicely organized sandbox. They still support the “Arduino” C++ libraries, but uPy is the default.
Using python makes sense though - it widens the user base. Not everyone is a C++ guru.
Adafruit actually focus on CircuitPython which is a fork of Micro Python but takes some of the complexity of Micro Python away. I don't personally like coding in C++ as I started my career with Perl then PHP and Javascript. Writing Python in my own choice of text editor instead of the Arduino IDE is much more my style.