Which course is better in IIITM Gwalior for a 5-year integrated course or a 4-year B.Tech in CS?

You should surely take the 5-year course because it is quite convenient. You will get really good placements with the 5-year course. Additionally, with the 4-year course being just newly introduced, the placements will take some time to develop. The IPG faculty is very good as compared to the B.Tech faculty who are novices.

Moreover, you will also save an entire year. If you are interested in coding, you will get an extra year to hone your skills and improve them which would eventually lead to better placements. So between the two, choose the five-year course.