Anime
Both franchises have shows that played a big part in why the franchise have become so popular. While the general idea of kids befriending creatures were similar, there are some noticeable differences in the shows. Digimon kicks off with a bunch of kids at summer camp who get whisked away to the Digital World. What follows is a fight to save not only this new world, but the kids’ own world as well.
Pokemon is a story about a young boy named Ash traveling the world with his trusty Pikachu to be the best Pokemon trainer there ever was. Of course, there are new regions, new Pokemon, and new characters, but the story is linear in that it always follows Ash on his quest. Pokemon tends to follow to follow a similar formula throughout the years; Ash is trying to be the very best and Digimon will always be about some kids trying to save the world.
Yet, Digimon does tend to shake it up every once in awhile. Even if the main idea remains the same, the settings and characters will change. They tend to start with scratch for their own shows, only going back to older material recently. Which is something that works for Digimon; meanwhile, Ash is still 10 years old (somehow) when he befriend these powerful creatures. There’s nothing wrong with what works, and that’s why Pokemon is still going to this day. It just works.
Which show you would want to watch would depend on which you like more. Digimon tends to offer more variety through its narrative, which means fans can pick and choose which season they wish to watch. Meanwhile Pokemon sticks to the tried and true with little to no difference in its plots.