I am an undergrad student and i have been through a first easy course on electrodynamics and i have used the book of Griffiths which let me satisfied.But the next two courses I will be taking are notoriously hard mathematics-wise so i want a step-up from Griffiths. I want a mathematically rigorous and comprehensive book that also builds up intuition (because physics is not only maths).
I have looked at Purcell's book and found it very pedagogic, it impressed me but I do not know if it is as difficult as I want.
Do you suggest that I buy Purcell's book or do you have anything else in mind?