I've always used bumper view exclusively, however, and this has been discussed in the Corvette C7 TT thread, after trying CHASE view for the C7 around the 'Ring I was able to bring my times down significantly.
I did the same thing with the AMG Academy event in the Special Events having got all silvers only the first time around in the game and usually only able to get to within 3 to 4 seconds of the gold time and improve no further. I have redone them using Chase Cam, and have so far golded all events up to Intermediate 3. The change to Chase Cam was entirely down to the difference.
I still prefer bumper cam as it gives, for me, a better feel for the game. But where necessary I will be using Chase Cam if it's gonna give me the results I'm chasing.