This is my first proper exposure to the Digimon franchise. I wanted to give the franchise an honest try as someone who always wrote it off as a Pokémon ripoff, and everyone was banging on about how brilliant Tamers was; I'm really glad I gave it a try, because it sure left a mark. To start, all 3 "main" characters were excellent; each of them had distinct, 3-dimensional personalities and grew significantly over the course of the show. From Rika learning that there's more to life than fighting, Henry slowly growing to trust Terriermon and Takato becoming more courageous / resolved; their characters arcs felt natural and complete. The supporting characters (apart from Ryo, who felt very shoehorned in) were also great. Kazu and Kenta added some much-needed levity to the back half of the series, and the viceral depiction of Jeri's Depression after losing Leomon was both highly impactful and surprising to see in an anime that aired on network TV in the early 2000s. Even the adult characters: the Tamers' parents, Yamaki and the Digimon Creators, had more depth then I expected; especially Yamaki who goes from hating Digimon and the Tamers to fully supporting / trusting them by the end.
My favorite aspect of the show was Takato and Guilmon's relationship. It was incredibly sweet seeing the unconditional trust they had for each other, and the gradual deepening of their bond from Guilmon essentially being a baby who doesn't know anything and Takato seeing him as a living toy, to being able to merge together and fight as one unit. I liked the relationship between Henry / Terriermon and Rika / Renemon as well, but I felt like Guilmon being Takato's OC, and the responsibility he feels towards him because of it adds an extra layer to their relationship that isn't present for the other pairs. It was geniunely unnerving when Guilmon Digivolved into Megidramon and seeing its puppy-like personality completely vanish, with him becoming this violent, ruthless looking monster. It really conveyed how beserek and off the rails Takato had gone; and I feel like that moment wouldn't have worked nearly as well if their relationship wasn't so solid beforehand.
One of the biggest flaws of Tamers to me was the excessive amount of fights. I get that fighting is Digimon's "thing"; but many episodes felt like they had a villain forced in to create unnecessary conflict. I wish there were more episodes dedicated solely to the relationship between the Tamers / their parents / the Digimon; since there were few if any apart from the very start of the series. I wasn't a big fan of the fights themselves either. They mostly came off as repetitive, with the Digimon continously using the same attacks / tactics and needing various Deus Ex Machina to swoop in and save the day. The worst example of this was with Alice and Dobermon popping up out of nowhere to give the Tamers the power to bio-merge in the Real World, leaving, and virtually zero explanation being given for how they did that. The "Deva" plotline that drove a large portion of said fights is also abandoned close to the end; with the Tamers failing to beat the Big Bad Digimon Sovereign that was built up to be the ultimate threat and it being replaced with a new ultimate threat, the D-Reaper. I don't mind the D-Reaper arc, honestly I think it was by far the best villain in the show both conceptually and in how all the characters play a major role in defeating it. But I strongly disliked how it essentially invalidates the ~50% of the show the Tamers spent running around trying to beat the Devas.
As for the ending... as tough it as was to swallow, it felt like a good conclusion to the series. In my opinion, it really tied in to the theme of forgiveness the show seemed to be pushing (eg: with Impmon being redeemed, Rika reconciling with her parents) with Henry's dad being revealed to have known the Digimon were going to have to head back to the Digital World and the implication that Henry's able to forgive his father (evidenced by him smiling even as he shakes his head no to the claim he's going to eventually feel better). It's very bittersweet, especially with how much everyone's been through by that point; but it definitely felt more on the "sweet" side with Takato discovering a Digital Portal in Guilmon's old house. My understanding is that the timeline splits from there, with the Digimon being back in a movie set after the series called "Runaway Locomon". But still split up and the Digital Portal being revealed to have been too small to transport Takato to the Digital World, instead having to send audio messages in a CD drama released by the original creator. They do still reunite in a sequel 2018 CD drama, and Takato's able to make contact with Guilmon in another sequel that was voiced at a 2021 Digimon convention. But that 2021 event also had the Tamers literally fighting "political correctness" (not a metaphor, the main enemy is literally called "political correctness") and doesn't even cleanly wrap up, with it ending on a "To Be Continued" titlecard. So I consider the Runaway Locomon timeline to be more canon since the CD drama one is incomplete and totally silly to boot.
Overall, it's a fantastic show, there are definitely some problems. A few too many Deus Ex Machina moments that solve the character's problems, too many fights in general; the whole "Digi-modify" concept that incorporated the cards being pretty much dropped once the Tamers enter the Digital World, and a few other minor nitpicks like the intro getting annoying by the end. But I greatly enjoyed watching it, and it's made me something of a Digimon fan after having nearly 0 interest or knowledge of the series prior.