Grand i10 Asta(O) MT - 5.47L ex-showroom
Elite i20 Asta MT - 6.47L ex-showroom
The price difference of top end petrol MT version is 1L(source:carwale) and i20 is a "premium hatch", whereas G-i10 is just "hatchback". Some features are carried over from i10 to E-i20, but the price difference of 1L means, it is intended for different category.
Also, E-i20 backseat comfort is a lot better among the two.
, Hyundai eliminated 6 air-bags and rear disks in E-i20 so there is no Asta(O) trim. So, if you can pay for this difference, then E-i20 is not a bad buy. But if you are strict on budget, G-i10 makes sense.