Quoted By:
1. DP - overall Best Gen for the anime. Dawn is the best female lead the show ever had, contests were really cool to watch, Ash was a powerhouse, Paul was an excellent rival and nothing beats Ash vs Paul in the League. Also the Team Galactic and Hunter J stuff was great.
2. Kanto: It has the most inspired filler of any gen and that alone is enough to make it worthwhile because the setups are actually interesting whereas I wouldn't blame people for asking for lists of what episodes to skip in other seasons.
3. XY: Animation is obviously a big factor here but Clemont and Bonnie were enjoyable members of the cast, Serena was unfortunately stunted personality development wise until about midway when the writers remembered she is more than just a love interest for Ash. And of course, the Team Flare stuff was great.
4. Advanced, as mentioned, this was basically a prototype for DP. May is the second best protag in the series but is dragged down by Max taking up screen time and unfortunately Veronica Taylor had to step away from her role - when her voice for May is just perfect, probably my favorite voice in female Voice Acting ever. Also the animation was really bad, like a glorified slideshow. Too bad almost nothing happened with Aqua and Magma despite the huge potential. Also Ash was kinda annoying this gen.
No real opinion on the rest.