I've actually made a crappy graph just to see how each gen fares according to my taste. I made those tierlists for each gen, where the tiers went from s to d, with s being favourite, c mediocre and d i hate. As all gens have different ammount of mons i did it in percentage, like how many percent of a gen is in what tier. Orange is KANTOOO, light blue johto, light green hoenn, brown sinnoh, unova darker blue, kalos yellow and alola is dark green.
Turns out i really love hoenn, unova slightly less, k^kanto, johto and kalos are pretty ok, hate sinnoh and despise alola. I've been playing since red