Adventure: I like how they made something nice and creative, and the character depth, the kids' relationships with each other and their digimon, I didn't like how the dub dumbed down some great things (apocalymon's speech anyone?, even if you haven't heard the original you don't have to be a genius to see there's something off with his dialogue, I noticed by the way kids seemed terrified, saddened at hearing his words, ot a usual reaction)
Adventure 02: I liked the continuity and some of the sory, also that some of the old guys stayed, but I didn't like the plot too much, some holes here and there o1o
Tamers: at first I didn't liek the change, it was all new, and well, I cared less for the characters because everytihng I knew from the first seasons was just deleted, but as it went it got great, so it was good o!o
Frontier: Same than with tamers, new characters, no connection, but I started to care for these sooner, and I liked how like in the first they had depth, though the idea of they being their digimon, well, made interaction a little more common, also, as Hanako said, later on only Takuya and Koji really mattered o!o
Savers: I really loved this season, cause of the more active participation fo the humans, unlike the first three where they just watched, what I didn't like was the same thing, the unfamiliarity at first and how nobody got along with nobody, but that ended quickly, also the end was a bit sad(don't wanna spoil it)
that's my post o!o