I played through these games back-to-back last year.
My impressions were that Ages hasn't held up very well from a world design aspect, and having played Seasons first made Ages feel like a real slog afterwards. (Maybe that was just fatigue with the series though?) There were some cool items/weapons to find, and more focus on enemies/combat... but also more focus on linear progression and tedious fetch quests.
Seasons felt a bit easier to progress through, although required more time exploring and trying to discover where to go next. It was also a bit heavier on puzzles, as you have to switch seasons to uncover secrets in different areas.
If playing them again, I would probably start with Ages and then do Seasons afterwards. Sort of a "save the best for last" approach - although other people might disagree about what aspects of the games are the best parts. If I could change one thing about the games themselves, it would probably be dropping the connectivity required to see the "true ending". Although I kind of enjoyed the sending codes back and forth to unlock little bonuses, I found it tedious to have to beat both before being allowed to fight the real boss. Neat idea, but maybe not as good in execution when I look back so many years after release.
Very curious to hear what people think of these games. They might end up being some of my least-loved portable Zelda titles... but were still pretty solid adventures.