Hi TK. It really has to do with the processor family that you're using. Personally, I use HI-TECH for the PIC16fs, and C18 for the PIC18Fs. My favorite of the two is definitely C18, but I only recently started using HI-TECH. There is also a HI-TECH compiler designed for the 18Fs, so it's really the kind of thing you need to decide for yourself. The best thing about HTC and C18 is that the lite versions are free, whereas mikroC requires a license (unless there's a lite version I don't know about).
Anyway, it all comes down to personal preference. Try a few different ones, spend some time with each one, and see what you prefer.
I hope this helps!
Regards,
Der Strom