Both the cars are very good, and have their own positives and negatives. While Grand i10 is a more premium product and comes with better features, the Swift is more on the performance front. It drives better and has better and refined engine. So, it's on you, for which one you want to go
That's great if you are planning for a new car. It might interest you to know that Hyundai is planning to launch the facelift version of the Grand i10 sometime this year around August/September. The Grand i10 facelift is also likely to get AMT (Automated Manual Transmission). So if you are planning in 1-2 months, we suggest you to wait for its new facelift version and other new upcoming cars.