There's no real reason to play the original gen 1 Pokemon games besides novelty. While they're perfectly playable, they're dreadfully slow and very simple. The GBA remakes of the first gen are the way to go. They're very faithful and exist beyond the major growing pains.

Pokemon Yellow specifically, I wouldn't choose over red or blue. Pikachu isn't the greatest starter you could ask for and he can't evolve. You can still box him luckily. There are some additional changes to the game that don't really add much to the experience. Sprites are different from the originals. Some sprites are better and others not so much (imo). It's easy to see how these games became a sensation though.

I would not have completed this game without the fast forward on my game boy (dad works at nintendo).