What are the differences between the games like Pokemon FireRed, Pokemon Emerald ect?

Question

Which is the best/most fun for me to start on?

What are just some minor and major differences between the games, do they affect the gameplay?

Comments

"Which is the best to start on?" is a very subjective question, but I can tell you that Heartgold, Soulsilver, Black, and White are the ones with the best reviews on websites like Metacritic, Opencritic, and Backloggd.

---

It would be easier to answer this if you gave some examples of things you want compared between the games.