Mt. Komorebi really is a beautiful world, and the houses designed by the game changers are great. Skiing and snowboarding are beyond anything we got in the way of winter sports from the earlier Sims games. I really like the hairstyles and some of the clothing. Hiking looks as if it will offer quite a few varied experiences, not just in terms of which hike your Sim goes on, but what happens during the hike.
Those are the main positives. On the negative side, players who already own Spa Day, Kids Room Stuff, and Fitness Stuff are going to feel somewhat annoyed by recycled activities. I suppose the best way to look at it is that you can use the indoor rock-climbing wall to gain skill before going out on the mountain, your Sim children will be able to acquire voidcritters in a new way, and you'll be able to add incense to the bathhouse if you have those packs.
The other negative, which I hope will be addressed soon, is that townie Sims show up on the slopes dressed for summer, swimming, sunbathing -- anything but skiing in the snow.
I haven't played long enough to have a Sim develop a lifestyle. Children don't get lifestyles, but teens can. A couple of my Sims have been told that they've capped their lifestyle points for the day. I think they get 20 points towards a lifestyle and when they reach 100, they pick that up. I might have a Sim start drinking more coffee just to get one that's a caffeine addict.
I had trouble getting my Sims to ski. I sent a Sim and her 2 granddaughters up in the ski lift (this works like the elevators in San Myshuno in that your Sims will arrive instantaneously), and then spent 10 or 15 minutes trying to figure out where the bunny slope was. Eventually one of the children decided to go down the easy slope on her own, and the grandmother got in line for the bunny slope (there was no line). I think if you buy the skis from a vending machine, the Bits & Bobbles, you might be able to choose the slope by clicking on the ski. At least I hope that's the case. The vending machines will take your Sim's money sometimes. Children can't risk death by hitting the vending machine, though.
Edit to add: I'm really glad that Sims can take off their shoes when they come home. On the other hand, I'm disappointed that they still have no winter hats that cover their ears, although there is a helmet and goggle combo that might do the trick.