IMO it’s the only film in the trilogy that’s a true serial installment. Star Wars was a one-off fantasy adventure that built a world for you, and left some threads open for future films. Jedi wrapped up all the loose ends and put a bow on top. But Empire was a serial – you already knew the characters, you had an adventure with them, and the adventure ended with a ton of loose ends and cliffhangers to follow up on in the next installment. Some dig that, some don’t. I really do.
Also, Empire maintains a split storyline longer than the other films. Some find it unfocused, but again, I dig it.
As far as other things go, the music is best in Empire (which is why the Special Edition is such a shame, because it mangles one of the best parts). The romance is definitely a product of its time, to put it generously.
I personally love Lando, but can completely see why he gets choked. He may be rescuing you, but he (perhaps) killed your lover/friend five minutes ago in front of you. So yeah, choking.