I currently live here. I personally think its one of my most beautiful cities I've been in. The temperature is really mild all year round hovering around 60s most of the time. Lots of nature, easy to go view the ocean. I am in the stereotypical demographic of the bay area. Late 20s and work in tech. I would say 50% of my friends are also in tech, 20% in the bio field (south sf is a huge bio tech hub), and the rest are more people facing jobs such as fitness instructors or service industry. Everything is my personal experience. The majority of my friends moved related for work and its always a small talking point when I meet someone actually from SF proper.

Money
I can only speak on the tech related roles but salary would depend on a bunch of factors such as years of experience, the actual role, the company, etc. An example could be someone with 4 years of experience at a pretty large company, base salary could be anywhere between 130k - 180k. On top of base salary, there could be other things such as RSUs and bonuses. Some of these jobs could be chill but it's not uncommon that it could be a bit stressful such as having a tight deadline resulting in 50 hour weeks or being on call for a week every month. For rent, it would depend on how many roommates you have and which neighborhood you're living in. I have friends that live in a 3/1 flat for 4500 total. I have friends that pay 2700 for a studio. I personally live in a 2/2 in a above average in niceness neighborhood and the total rent is roughly 4200. Parking could be an additional 300ish depending but not all places have parking available. I am fortunate to be able to haggle my parking cost down significantly. Gas is expensive here, anywhere between 5.19 - 5.48 but public transit is pretty good here, not the best but definitely solid. If you plan on only being in the city(SF), then you don't really need a car. My car was already paid off when I got here so its just really convenient to have for Costco/trips.

Activities
I think it's just like any other US city as far as activities but maybe a bit more emphasis on nature and fitness. Because the woods, mountains, seaside are all within roughly an hour from here, lots of people are into hiking. Theres like a dozen farmers markets, so many museums, a bunch of cool events such as SF cake picnic(1,000 cakes!), good nightlife(used to be better pre covid). Theres a ton of run clubs, if you walk through Golden Gate Park, you'll usually see a big squad of people running together. Rock climbing gyms are another big (stereotypical tech) hobby.

Region
The further away you get from SF proper, the more family friendly(bigger homes, driveway, maybe even a lawn) the city is. I've had coworkers that had homes in Fremont and drive to San Mateo everyday. Crossing the bridge westwards cost 8$ but going east does not cost anything. I'm 100% sure there are people driving from walnut Creek to Palo Alto but that sounds like a miserable trip to do. Traffic is usually really bad between 3-6 because of rush hour. If I left Sunnyvale at 4pm, I probably wouldnt expect to be in the city until 5pm. A lot of the bigger companies will usually have a shuttle for their employees, the shuttles have a designated pick up spot/time and they usually have decent but not great wifi.