I am on my third pair of Brooks and cannot say enough good about them.  I run about 25 to 30 miles per week on average, weigh about 190 pounds and get about 350 miles per pair before I replace.  I could probably get more miles out of these shoes, but find that the feeling of a fresh shoe every 3 to 4 months refreshing.  I have used numerous other shoes, and with other brands had issues with knee pain, shin splints etc.  I have never experienced any of these things with the Brooks.  They are extremely comfortable for both hard surface and trail running.  I always buy the previous edition GTS 11 vs. GTS 12.  Over the course of a year, the price savings allows me to rotate my shoes more often for the same money which is more important to me than having the latest model.