After skipping EV3, which was too similar to NXT, this new set is very refreshing. The new brick and motors are, in my opinion, so much easier to build with than the former NXT/EV3 motors. Smaller and lighter robots are the way to go. The absolute motor positioning together with the new gyro and acceleration sensors within the brick itself offer so many possibilities for building and programming cool stuff.
Initially planning to code using Python, I tried the Scratch environment as well for testing simple movements while building a model; which was surprisingly powerful. I also like the option to make a custom controller on your phone with various buttons and sliders.
As for the fifth star, there are some minor details which could have been better. The gyro-sensor sometimes 'snaps' to 90 degrees, making it hard to detect small tilt; the motors have some internal gear lash, which makes really fine control hard to achieve; the motors don't run at (very) low power levels, but do make some electric noise instead. But none of which keeps me from having fun with this set.