The battle for the sub-Rs. 20,000 market continues to heat up almost every other week. Last month, we reviewed the Realme X which seemed like a great all-rounder phone in its segment, and now Vivo is taking things to the next level with its new Vivo S1. But if you have to pick one, which is a better option – Vivo S1 or the Realme X? Today, we'll find out. We decided to compare the Vivo S1 with the Realme X. In our comparison, we factor almost all important elements of these phones from design to performance, from camera skills to selfies, we look at everything to help you decide which smartphone is worth buying right now.