Anyday you should choose MNNIT over mnit jaipur although the rankings may not reflect but mnnit is a far better college just one disadvantage may be that allahabad is not as good a city as jaipur but even if yo compare it branch to cse of jaipur then also mnnit allahabad is better provided that it and cse are not much different branches. MNNIT has provided the best placements in average terms over all other nits so on placement prospective also mnnit is better.