Judging from the many, many previous discussions of this topic on this forum Keil is better. I don't know whether this is merely because more people use Keil than Raisonance, although there is a possibility that that in itself may have made Keil, or shown Keil to be, better. Note that the success of Microsoft does not support this theory.

Luckily for me I have only used Keil so I have no opinion to contribute.