Which of them is better in code size ?
Which of them is better in code speed?
Can Hi-Tech support all microchip librarys and source codes(peripheral lib , dsp lib, graphic lib, TCPIP lib, ......)?
Can KIEL support freeRTOS?
Can MPLAB support all intel librarys(mcu , mpu , lib, ....)?
Compare both and tell me what you prefer and why?
I think a Porsche is better than a MAN truck.
Don't you realize that you are talking about different processor architectures?
Why would a Keil (not Kiel) user care about the performance of MPLAB or what code HI-TECH compilers produces for PIC processors?
Go home and do some home work on what processor architectures you are interested in. Then start comparing compilers for that specific architecture.