I like Spa Day a lot. I usually have two Spas in every save and one club that does Spa activities and is named 'The Well-Beings' or something equally silly.
I like the workout clothes more than those in the Fitness Pack and it comes with an awesome two- piece swimsuit.
The Wellness skill is a great skill to have as your sims will learn to influence other sims emotions for hours, making them focussed, creative or confident. And the yoga mat workout gives your sim long-lasting emotions, ideally used before work or for skill building.
The pack comes with great venues but you can also place a yoga mat in any gym and an instructor will show up. I made an outdoor spa for my sims with the "Loves Outdoors" trait, for example.
It's a pretty great pack in my opinion.