Me too. I think rankings aren't that important in Europe and people tend to get jobs based on other things here.

tl;dr For a MSc try to choose a department with strong faculty in your area of interest.

I've been both at Cambridge and Oxford. I think Oxford has had a much better CS department for a number of years. A lot of Cambridge faculty was hired by Microsoft Research long ago and they never recovered. Google Brain has also drained a lot of their talent lately, mostly from the Engineering Department.

Oxford has tons of famous people now: Luca Cardelli, Marta Kwiatkowska (formal methods), Yee Whye Teh (Bayesian non parametrics), Dan Olteanu (database systems) and others.

As for mainland Europe, I agree ETH and EPFL are probably among the top. I would also consider French CS, which is super good. Any French department associated with an INRIA in the topic you are interested in might be a great choice. In particular, ENS Paris might rival with ETH or EPFL in terms of quality.

Lots of smaller Scandinavian, German and Belgian / Dutch unies might be a great choice too. E.g. UCL Louvain, DTU, etc. It really depends on what you wanna do.

How can I know if there is a "strong faculty in my area of interest"?

H-index on google scholar?

University Rankings are like the Body Mass Index of figuring out how good a university is - not entirely useless, but not to be used as anything more than a very rough gauge of what's going on.

That said, QS break down their (global) rankings by subject. Below is the link for computer science.

https://www.topuniversities.com/university-rankings/universi...

There's no easy way of telling how much better the nth-ranked university really is compared to the (n+m)th-ranked one, but it could be informative nonetheless.

That's a decent starting point, especially in CS.

If you wanna disclose your area of interest I may be able to point you to some departments. Contact information is in my profile, if you prefer email.