I moved to Zurich in JAN with my partner and we've had two very different experiences.
For me, it's been relatively easy and I guess that's down to having a job, not looking for a "bestie" and the fact I can enjoy a drink with pretty much anybody. Without sounding ungrateful, I'm already at the point where I have to turn down drinks, dinners, coffees et al.
For my partner, she's struggled and I feel the blame is split 50/50 on her and the environment. I guess you have to speculate to accumulate, which means you need to get off your backside, meet new people and then sometimes accept you didn't back a winner. I do sympthize with her however, as I see the environment to be cold, reserved and/or just plain boring!
A friend recently pointed how Zurich completely changes when the sun comes out - it's like "rent-a-crowd" - and I guess this will have a huge impact on the social front, so I'll circle back later in the year and I'm sure all issues will have sorted themselves out....fingers crossed