Hello Aspirant ,

B.Tech+ M.Tech combination is much better than BCA+MCA as it is a much more practical and professional course compared to the former. B.Tech offers amazing placements after graduation and covers a lot of subject in 4 years , i.e, both hardware and software. However for BCA , most of the subject is confined to coding and software part and anyone with an interest towards computers can do it. But B.Tech is exclusive to students who've done PCM in their. 12th. MCA is mandatory for students who want nice positions after BCA as the placements are all entry level after graduation. M.Tech abroad and in top tier colleges in India is very lucrative and gives more edge. However B.Tech+ M.Tech is highly competitive and you need to ace the entrance examinations like IIT-JEE and GATE  for admissions.

The scope of employment in B.Tech is vast and there are heaps of fields you can choose from but BCA is only confined to the IT sector.

Hope this helps you! Good luck!