Yes, the Easter Vigil Mass fulfills your obligation for Easter Sunday. However, I perfer to go to both, because the Easter Vigil is a great night for the church. Our Lord triumphantly rises from the grave, new members are welcomed into the church and become Catholic. The beginning of the Easter Vigil is solemn and dark. We begin with the lighting of the Easter Candle, and then the Exsultet (Easter Proclamation). Then, we hear the fundamental for the whole Easter Vigil - the Word of God. As stated in my missal, the main fundamental for the Easter Vigil is the Word of God. After all seven Old Testament readings (shortened for grave pastoral reasons in some parishes), the Gloria is then sung and the church lights are put on. Then, we have the reading of the Epistle, and then - the biggest musical score of the Easter Vigil - the return of the Alleluia. We haven’t sung this since the last Sunday in Ordinary Time. Then, the Gospel is read, and we watch the members of the RCIA be brought into the church. It’s truly magnificent!
Easter Sunday starts with great joy from the start all the way until the end.
In my opinion, it’s best to attend both because they are both different and unique in their own ways. The Easter Vigil starts solemnly, while Easter Sunday starts joyfully.