Hello Chris
A BSc at a University or at a Fachhochschule has the same level (tertiary level ) but a different orientation.
Please note that we speak here of public university and public Fachhochschule.
Roughly, Fachhochschule is application oriented (= University of Applied Sciences), University more theoretical (fundamental research) oriented.
It all depends what you want to work later and where your competences/interests are. A very important question is: where do you want to use a swiss degree later on? If you plan to go back to Mexico sometime (or if you plan to move to other countries), check by the mexican authorities if they recognise a swiss public BSc.
Beforehand you may want to check if you fullfill the prerequisites to study and stay here after your studies. For this, have a look at
www.crus.ch (study in CH). There you will have a link to swiss public universities.
For Fachhochschule the best link is:
www.kfh.ch.
Please note that a BSc at a Fachhochschule gives you the competences required from the labour market (the BSc at a Fachhochschule is "berufsbefähigend" as it says in German). So when you have a FH BSc you are ready to apply for a job. This is not the case for a BSc at a University which you will complete with a Master before applying for a job/position.
I hope my infos aren't too confusing
FMX