I honestly preferred BW, BW2 felt a bit lazy to me. The story was really half-assed and didn't feel a necessary addition to what was presented in their predecessors.
It was a neat experiment, but for all intents and purposes, it was probably my least favorite pair of the series. I loved the "fresh start" in BW, the new world, the way the characters were all presented, it was all very well-thought-out whereas BW2 didn't give me the same feeling. I liked the new side features, but other than that, it fell apart in other regards.
Half of the massive regional dex wasn't even accessible until post-story. That was pretty cheap imo, why bother having such a huge national 'Dex? I don't know, I feel in the minority here.