Actually 'Our candidate is better than you' can be either Vår kandidat är bättre än du/ni or … bättre än dig/er. Both ways work in Swedish. In this case English is helped out by yours, but in a sentence like Jag är längre än han/honom, both ways work both in Swedish and in English: 'I am taller than he/him', so this often works the same in both languages.
än and than are grammatically ambiguous, they can be seen either as a prepositions or conjunctions here.
Arnauti, I cannot answer your comment, so I'll answer here. I still do not get why the Swedish sentence is ambiguous - I've thought that "Our candidate is better than yours" would be "Vår kandidat är bättre än din/er" while "Our candidate is better than you" would be "Vår kandidat är bättre än du/ni (är)".
er is the second person plural possessive pronoun for an en word, as well as the second person plural objective pronoun.
If you were talking about an ett noun instead of a kandidat, you would use ert, or era for several candidates.
Our table is better than yours: vårt bord är bättre än ert
Our apples are better than yours: våra äpplen är bättre än era