I buy this model gp 305 because it claim to have better satellite range and reception , every run I use it on , I keep loose the satellite , the pace per mile would jump from 9-10 min . mile to 2-4 min . mile . it would give I the average pace per mile , but not the max pace per mile , this be a replacement for the gp 205 that I have , which never give I any trouble . I will probably go back to the 205 .