I just got offered by all 3 schools recently and I am stuck making a choice actually. Some of the points that I have worked out so far

1. INSEAD - based on research, it seems like INSEAD gives the best boost to those who wish to join the big 3 consultancy firm post graduation. However, it came at a cost that is more than double of either NUS or NTU. Alumni network is strong but my intention is more focused on Asia rather than the western hemisphere.
2. NUS - course structure wise seems to be quite attractive, attended many of their coffee chat and meeting with current students and alumni. Culturally it will be more relaxed for me. Alumni network is strong in Singapore.
3. NTU - adcom admitted that consultancy may not be their main selling point but if anyone is looking for the tech space, NTU is confident in its programme and alumni network. Cost wise the lowest as well among the 3.

I had made up my mind to go to NUS before i received an email from INSEAD! I got out of the wait list. Experts, seniors and those who has walked the path, some advice please?

Will there be a stark difference in terms of post-graduate job opportunities/salary. I am inclined to consultancy and private equity post graduation.

I think this depends on your background. I would pick NUS. 

I think this depends on your background. I would pick NUS. 

The NUS degree is longer and more extensive. I think it's a good fit for someone not already in consulting and who is focussed on the regional market. Insead is more intensive, and suits people accelerating in their current industry. 

INSEAD's program is much more intensive, whereas NUS has an awkward winter break where you can't really find a proper internship opportunity. 
The professors at INSEAD are top notch, and many classical cases are indeed written by INSEAD faculties. They aren't really comparable because they really aren't in the same tier. Almost half of the class at NUS MBA are part time candidates, and they really are a whole different story. 

It's an assumption that someone called Robert might not be well-networked in SG, but I would start from there. An intensive program is excellent if you are accelerating in the same direction and are an obvious hire for an established hiring partner. A longer format works better for networking, acculturation and informational interviewing with potential employers.