I’m Italian in my mid 30s, and have been living in Lausanne for 12 years now. My overall feeling about people from Lausanne is that they are relatively open minded, for being Lausanne what it is (not a major city or capital, but a 130k inhabitants town surrounded by mountains). The presence of universities in town definitely shapes its lively attitude, and compared to 10 years ago now you feel more diversity around.
People are probably more relaxed and easy going than in the Swiss-German side and less formal than what you may find in Geneva, but making friends is still not the easiest nor the most spontaneous activity. They say it takes at least 5 years to start feeling “integrated” and having some swiss friends in your entourage; of course this is a generalisation but I do recognise my own experience in this timing.
Some say Lausanne has gotten “worse” and more dangerous in the last years; I personally never had any troubles and have always felt safe at all times.
Compared to other Mediterranean towns of approximately the same dimension (I’m comparing to what I know) Lausanne is probably more functional and better organised, which of course helps making your every-day life smoother, but has its downsides sometimes. When walking in the old town on a Sunday it might make you feel like being in a ghost deserted place, with almost nobody around. But, for example, during the old town festival (fête de la cite) there will be a million people packed in the streets: it seems to me people need an officially organised event or an official reason to go down and walk in the streets, otherwise they won’t do this spontaneously. It could be a bbq with friends or a city event, but for sure there’s much less or almost no “stroll culture” as we know it in the Mediterranean area. The little sponteanity in people is what I found the hardest to get used to, but I guess coming from the Mediterranean area I would have felt the same mostly everywhere in central/northern Europe.
Something I like very much instead is the shared sense of care that people have for their town and country. They keep it clean and organised and this has always made me feel respected as a citizen.
I do recommend Lausanne as a place to live in.