These episodes cover quite a lot of events in the series. Sure, Ash gains a couple of badges, and while exciting, that's expected and not really part of what has made this series so fun. In this boxed set, not only does Charmander evolve into Charmeleon, but after a couple of episodes jumps up to Charizard, surprising everyone... especially since from Charmeleon on, the Pokemon doesn't want to listen to Ash anymore.
In the same episode where Charizard comes on the scene, the gang stumbles upon an area where prehistoric Pokemon are still alive and before leaving the ancient cave, Misty finds a Pokemon egg. I remember when this series was first aired; this egg was a big deal. When it was about to hatch, it was going to be a brand new, never before seen Pokemon (mind you, this series was during the Pokemon Blue/Red era), and eventually became Togepi (from the Gold/Silver games), and a whole episode is devoted who will get to keep the little guy. After all, Misty found the egg, but Meowth thinks he deserves Togepi because he helped hatch it, and so on.
This group also introduces Jigglebuff, a Pokemon that follows the gang around Kanto and some of Johto. This character was always an enjoyable comedic relief as it occasionally popped up, sang its song and got mad and wrote all over people whenever everyone falls asleep.
This DVD collection brings together all of the episodes that aired here in America. This means that it doesn't have episodes like "The Legend of Dratini" and "Electric Soldier Porygon" which I had heard about way back when the show first came on and was sort of miffed when I didn't get to see these shows. But alas, they have evaded me yet again.
As far as recommendations are concerned, this show obviously already has a major following. If you haven't been following the show since the beginning, then you might want to pick up this and the previous boxed set to see how it all got started. If you have been watching for all these years (personally I fell out of the series quite a while back), then you should probably jump on Pokemon Indigo League Season 1: Vol. 2.