Considering the general opinion, IIM Jammu is way safer than NIT Srinagar. Some reasons that support this opinion are 

• Less terrorism in comparison to NIT Srinagar 
• The climate is almost similar to Delhi with minimal snowfall 
• Curfews are imposed rarely only during serious situations
• The president's rule does not affect the education here.

On the other hand, NIT Srinagar 

• has frequent cases of fights among students 
• has a sort of anti-Indian environment 

The only drawback of IIM Jammu is that it just has a temporary campus whereas NIT Srinagar has been established for years.