Southern California was a lot of fun - I crammed a lot into my time there (possibly a bit too much, as you can tell by the infrequency of my blog updates). Engineering-wise, it is home to so many Aerospace companies that I am highly likely to visit, or be invited to work, there at some point.
The climate is hot here, but I was able to manage fine and adapt quite quickly. I certainly wouldn't want an outdoor job, neither could I bear it much hotter, like it is further inland. Geography-wise, I was pleased with how quickly I could get used to covering large distances by road, a 2.5 hour drive wasn't much of an issue by the end of the week, even though it would get you to Nottingham or Dover from where I live in the UK!
American cities are just normal cities at the end of the day, so apart from the slightly different road network planning, I can't see too many differences here with cities I'd live in in the UK. It seems like any activity I enjoy doing in the UK, I could do just as easily in California, it just might take a bit of a further drive than usual.
Driving around the state was probably a highlight for me - the Californian road network is very good indeed (although I never saw it in the morning rush hour) and I loved the 6-7 lane freeways - they were varied enough to keep interest and went through some fantastic scenery. The highlight, of course, were the meticulously crafter country roads with their good use of camber, excellent surfaces and markings, and great fun weaving through the scenery! The American drivers are a bit more robotic than the UK ones, for instance if you want to change lanes on the freeway, you can indicate all you want and no-one will react; it's up to you to find a space to move into. Also, people just stay in one lane until they come up to a car going slower than them - at which point undertaking is just as permitted as overtaking. I had no problem with this, though I watched an amusing compact convoy of cars on a two-lane highway as one car refused to accelerate to go past the other!
The American people, then, are what make the real difference. I came across some very friendly, helpful people, both in my company visits and around the cities I was visiting. It seems like most citizens could be switched into friendly mode - but you had to initiate it! There was much less impromptu interaction than I've seen in the UK, but again that could be a feature of being in the cities.
I think I could very easily live and work here, and adapt pretty quickly as well. What would annoy me would be the fact that prices are never actually what they say they are. What I'd miss would be the variable climate (especially soaring weather) and the shorter driving distances of the UK. But apart from that, I think I could safely say that California is for me :-)