B.Sc. Computer Science is 3 years of Graduation course while BTech is 4 years of Graduation course after which you will get Engineer's Degree.

Btech can be chosen if there is no fees constraints and if you are getting a good college for Btech studies.
It is a more professional course than Bsc and the benefit is you will get more industry exposure. Also your placement and package will be good than general Bsc.

Rest depends upon you.

Good luck.