If you go by ranking then nit trichy is best but ranking does not tell the real scene nit allahabad has best average placements among all nits and even better then some iits yes you heard that right and not one these placements in nit allahabad are slowly breaking great barriers and have crossed half a crore mark this year in CSE department but all 3 colleges you  mentioned are good and it more or less depend on you which one to choose. If you are still confused you may go ahead with nit trichy if language barrier is not a problem for you