Hey Gurpal,

JEE opens the gate to IIT's and NIT's, on the other hand BITSAT is entrance exam for admission in BITS only. As we know, for all engineering aspirants IIT is a dream. So, yes it can be said that JEE is better as it also allows you to contest for a larger no. of seats than BITSAT. But since the preparation of the two exams is almost same, you should apply for BITSAT as well. It is comparatively easier to crack but demands speed and accuracy. 

All the Best!