I did my Bachelor (bilingual) and Master in Computer Science at UC3M and my experience was good overall.
You find professors that are really passionate and the collorary is pretty broad, while allowing you to go a bit deeper whenever you are interested in something, mainly through the practical projects.
The first 2 years are always quite Math intensive but then it gets fun. I think it is better to take it easy and enjoy it a bit instead of pushing through the four years, because if you want to really do all the practice assignments you will find yourself with basically zero free time.
Definitely would recommend the bilingual path since also groups are reduced and you can really feel the difference in the teaching