dear kumar
both of the exam are of same level , i mean the question difficulty will be equal at both the format of examination .
so, its all about your comfortability , the mode in which u attended mock test before the actual jee paper .
so, if u can sit for 3 hours in full concentration in front of the computer , then choose online , else offline will be better .
offline is the traditional mode of exam and u will take some time to bubble the answer in omr sheet here and also there is always a chance of mistake , but online – its free from any kind of error ,
so, in my opinion online will be the best option
HOPE IT CLEARS
ALL THE BEST
REGARDS