Thanks for the question 

All the colleges which you have mentioned are stand almost on the same balance  

Established in the same year and having private ownership , all three have a good infrastructure and faculty.

But one of the advantages of RNSIT is the placement. It has a bit of an edge over the other two colleges. Average package is over 5 lakhs per annum. 

Whereas jssit and sjbit have a package average in 3 and 4 lakh per annum. 

That being said, hostel life and accommodation of JSSIT is better than other. 

Finally it depends on your personal choice, where you want to go. 

All the best for the future