Vampires VS Get Famous

@dolljoonzfirst of all, the two are different types of packs - Vampires is a game pack, where as Get Famous is an expansion pack. GF is bigger, has more stuff associated with it, and costs more than Vampires.
Personally, I like Vampires, but ultimately, it really depends on how you like to play the game. The Vampires pack has a some nice Victorian-esque build-buy and CAS items and obviously vampires, whereas the GF pack is all about the glam and fame and acting.

You can look up what items are in each pack here:
Vampires: https://www.ea.com/games/the-sims/the-sims-4/pc/store/mac-pc-download-addon-the-sims-4-vampires
GF: https://www.ea.com/games/the-sims/the-sims-4/pc/store/mac-pc-download-addon-the-sims-4-get-famous

I also like look at Youtuber's reviews of each pack - if you search for something like "Sims 4 vampires pack review" or equivalent, you can see people reviewing the items and gameplay in the pack