The main reason I don’t use Macs, is that they are way way over priced. For example you will spend $1000 for a new Mac laptop, while you can spend $300 for a PC laptop.
To prove my point: Asus 14″ Laptop 2GB of memory and 320GB hard drive – $279

The 2nd reason I don’t use Macs is that they look really good on the surface, but once you dig deeper there is no follow through when you really have to use the device.
To prove my point with IOS6: