I've lived in a few major metro areas, so I'll take a shot at helping you. I'm interested in seeing if anybody else has run into these things happening to them, as well.

Coming from a background in CS, you have a definite advantage. There are a lot of tech companies out here, but I would not limit myself to that if I were you. There are plenty of opportunities where tech is an overlap with the actual focus of a company. Try not to get stuck in a particular mindset about what job you'll do, especially if you are just finishing your PhD and stepping into the "real world".

The Valley (I'm including all of the SF Bay Area, as well), is a great place, with a lot to offer. However, it can be a hard and cold place, especially if you don't know anybody out here.

Unless you're traveling along El Camino Real, or going into the center of cities, traveling is a pain. Services such as the Caltrain have limited stops at certain locations, and stop running at 10:30pm or midnight (depending on the direction). Muni can be packed and pass by usual stops if there isn't enough room (ususally will only happen around Chinatown and Northbeach areas). And BART is... a topic for another day.

This has given rise to Uber and Lyft providing a great convenience, but one in which you pay for. Sometimes having excessive multipliers on the usual fare you're charged. Taking an Uber in SF during a Giant's game day will see a spike in fare, for example.

The culture is its own thing. Having lived in Chicago and NYC, I've had my share of interaction with enough people. People in the valley are very friendly and very helpful—up front. Rather than not talking to you, or brushing you off, people will act very excited to meet you and talk with you. However, do not take this as them having an actual interest in you, or anything about you. This lone difference had made it difficult for me to actually understand who is a friend, and who is not out here.

Related to that, the dating scene out here is the same, from my experience. A lot of girls I've dated out here are looking for a guy who has a particular "thing". Whether that be he teaches yoga, has a dog, does art in the park, something they can tell their friends about. In NYC my experience has been a bit better. Girls seemed to be more attracted to me based on my personality, and "charm" for lack of a better word. I didn't feel the need to have a "thing" going on, just me being me.

Housing and where you live greatly alter your enjoyment. This also depends on what you want to do.

If you're looking for night life, you should definitely live in SF, Palo Alto, or San Jose. Anywhere else limits you to particular metros, or how much money you're willing to shell out for an Uber. There is a lot going on at any time in those 3 places, that finding groups, meetups, events, will be a great place to socialize.

Housing is expensive. Very expensive. But it's not terrible. A lot of companies take into consideration housing, so your paycheck will reflect being able to afford to live.

Your paycheck might look like a lot at $120,000, but it's not. Between rent, taxes, food, travel, you'll be living well, but not as well as some might think.

It's a good place to live, especially if you're in your 20's and want to further your career, and love technology. Outside of that, it's just another place with its own quirks.