While the extras are pretty cool and may be worth it to you depending on how you play, I personally would just get the standard version. I got the Serenity Retreat on sale for 50% off or so not too long ago - I haven't used it much yet, though I can see sending my dynasty sims over there if I want to attempt a formal wedding, and they'll definitely be getting an outdoor shower pretty soon, along with a massage table when they get more money. However, I'm glad I didn't pay full price for the venue, which you essentially would be doing if you got the gold version.
With the standard version, you'll still get the sauna. The extra 1900 is basically for two more pieces of premium content (the outdoor shower and the massage table), a wedding arch, a fish tank, a few other build/buy items, and the building itself.
