Choosing between IPU CET and COMEDK as they both are conducting on same date depends upon your choice of location. 

Both are good. There is no comparison between two exams.
Number of colleges and seats are more in COMEDK as compare to IPU.
In IPU, There are few Government colleges also which are decent. In COMEDK, All the college are private.
If you belong to outside Delhi then I would suggest you to go for COMEDK but if you belong to Delhi Only  then you should go for IPU CET.

Good Luck!!