I have no clue..who is who..so before posing a question, please give some background..it will help us answer better. From the above answers I can make out these are cricketers..but if we to answer without reading the above answers..i would have been clueless.
I think Suresh Raina is better as he has proved his worth many times playing for India where as Tewari never could proved that he has got a potential. I know Tewari is a talented cricketer but he needs to prove it and has to show selectors that he can play good even in international cricket also.
For ODI's Suresh Raina has scored more either through batting or taking wickets when compared to Tiwari. Another advantage is suresh Raina is left hand batsman and is more useful for Indian team. I prefer Raina over Tiwari by seeing these records of both for representing India.
I guess Suresh Raina is better.. Both are good, but Raina is having more experience plus he already have given some good performance for India on international level. So as per me Raina is more good option.