thats a difficult question to answer, its like asking which car is better....
Each compiler has its own advantages, you only have to see which one works to your benefit.
When I wanted to buy a compiler for my lab, I had several options.
1. Microchip-- A comprehensive compiler, best suited for PICs, a very good support forum, but pricey compared to others in the market.
2. HI-TECH-- Pricing was OK, but at that time (this was 5 years ago) they used a IDE that looked DOS based, and that put me off ( in any case I could have used MPLAB as my IDE).
3. CCS-- Pricing was competitive, good support. I liked the #use directive especially as its very easy to setup a serial port, I2C port or a SPI port with this directive. They also had a large library of drivers that was very readable.
So my choice was the CCS compiler, I bought the PCM version for 14 bit parts, now 2 years back I bought the PCH for the 18F parts.
thanks