I think we definitely have a better quality of life in Switzerland than in London. The reason being that we now have a child and we want to live outside the city. Here we can live 35 minutes direct train from the city centre but rent a big house with a big garden in a small village next door to farms, so we have both the easy commute and the more relaxed lifestyle. There are always seats on the train, dd has much more outside space, fresh air, animals, etc. I feel it's harder to do that in London as it's a much bigger, crazier city. However I know that some people who live in the really popular areas here experience the transport pressure I hated in London. I think the sheer effort of dealing with authorities when you only speak conversational German is the hardest thing for me, but couples with one Swiss partner don't have that problem!
I do miss our old social life, and all the opportunities to do things that there are in London, but realistically we wouldn't have had the same lifestyle in London with a child than we had before anyway. I'm also worried that if I give up the job I was lucky to find then I'll never find another one because my German isn't good enough. But if I don't give it up then I have to go back to work after 4-6 months maternity leave (14 weeks is legal minimum and you can in theory extend it if breastfeeding) as I really liked having longer off work with dd. I like earning money as it's quite an expensive place to live, but I also want to make a concerted effort to become more fluent in German and it's impossible to do this when working all week and looking after a child in the evening. So basically, the things I think and worry about now are not the same things that i used to worry about in London. When family come to visit I ask for cadbury's flakes, custard cremes, but tbh only because of the novelty not because I actually miss anything anymore.
I think if you have the opportunity to live abroad when your children are young it's worth thinking seriously about, as you don't need to worry about interrupting education, and there is the opportunity for them to absorb a second language. If thats also their heritage then there are even more benefits especially if they have family here. Switzerland is not that far, it's easy to go back and visit or to move back if you hate it. You just have to be prepared to put a bit of effort in to get the most out of it.