DP was awful. It was filled with filler. Hell, there was a YEAR gap between the Snowpoint and Sunyshore gyms
Season 1&2 were actually decent, recently watched Go West Young Meowth. The characters have so much heart and personality here.
Johto - Stories became Pokemon of the Day episodes, and always followed the same format.
Hoenn - I liked the new characters, so enjoyed more than Johto but almost always kept the Pokemon of the Day episodes, however battling got more enjoyable.
Sinnoh - More interesting episodes than Hoenn, really started to remove any traits of personality of the main characters with the new dub.
Unova - New characters are lame, literally can be summarised into catchphrases "so psyched" "such a kid" "something something flavours", battles lots better but stories are always lame - its tragic watching an old episode than a new one cause all the characters have basically lost any scraps of their personality.