Being honest I think that Universidad Politécnica de Madrid is the best Technical University in Spain with lots of years of experience since it is the oldest one. I had good references from friends so I did not doubt and applied to study there.
I think the best benefits is that the UPM is a really popular University and everybody knows how prepared are the engineers that study there. A good point is that since the UPM is the oldest technical University, when you go to an interview and it is with a manager or senior manager, most probably, he/she has studied there and you can have an advantage because of this. Last but not least, the UPM has really good Erasmus agreements with other Universities all around Europe.
I think that UPM does care about its students and the learning methods. They are as much digital as possible which is really helpful. Moreover, UPM has a lot of research departments if someone is interesting in a PhD.
I have missed more practicing sessions, lectures where you can get your hands on. I have the feeling that the lessons were too theoretical. On the other hand, the UPM should pay more attention to the little departments because they are quite old and not modern.