It all depends on how well you have prepared throughout the year.For me personally COMEDK was much simpler the KCET and I actually did not prepare anything specifically for that exam.
If you have given other entrance exams before COMEDk then this should be relatively easier to attempt.But take care of the speed at which you solve the questions.Speed is the most important factor in deciding your rank as there are no -ve markings.I would advice you to solve a few prev year papers and more importantly chill before the exams . That gives a lot of confidence during the actual test itself.