Hello,

The only advantage SC candidate will have in UPSC is relaxation in terms of cut-off.

While, for a General Category student, it's quite high compared to reserved category, this is where the advantage lies for students belonging to reserved categories.

Clearing Prelims is no an easy task, because for a majority of people, it gets difficult and this happens in the case of some extremely brilliant student as well.So, people belonging to reserved categories have this advantage, which is a huge thing.

However, coming to the MAINS part, there isn't any such advantage provided to anybody specific for that matter, because it's not mcq based test, it tests one's in-depth knowledge about the syllabus of UPSC.  There's so much to write for Essay Paper, GS I-IV Studies and Optional. This requires a rigorous amount of preparation in terms of knowledge and writing practice.

Hope, this helps.