I think it really depends on what your gameplay and build style is.
For me, I use Get Famous more now that my Sim family is wealthy because of the build/buy and CAS objects. I don't particularly care about my Sims being famous. However, I like to build fancy style mansions and I like my Sims to look wealthy.
Back when I was playing a farming family, I bought Outdoor Retreat and loved it. My sims rarely go on vacation anymore. However, the objects in this pack are a lot more woodsy and nature-inspired. The CAS items are also great for outdoorsy Sims. It also comes with a lot of new plants and fish, which is nice for farmers.
Tbh I don't care for the gameplay in either pack, though. I feel they both get old really fast. Just my personal opinion. I'd base my decision on the items I would use most.
