Doing mtech in IIIT lucknow in cse related streams is very good. In all the IIIT there is very good coding environment. So you can brush up your coding skills there. Placement wise it is very good as well. You can expect 80-90% placement in mtech cse. But like btech candidates placement may not rise to that much level for Mtech candidates. So highest package may be 20-25 lpa which again varies according to the batch and yearly situation of the college. But the undergraduates are getting more placement that pg students.