I buy the 305 from Amazon over a month and a half ago . I be to run a 5k the next day and hadnt try the forerunner before . I go ahead and wear the forerunner for my first 5k just to see if it would be able to perform and I be pleasantly surprise at how well it do ! this be by far the best purchase I have make . I use it for my run everyday and upload my datum to connect . -lrb- ... -rrb- as soon as I come home . its so much easier to not wonder or guess how far you run and what you pace be since the forerunner do all the hard work for you . I have be able to enjoy my run and improve my endurance a lot more by track my heart rate and slow down when it touch 170 or higher ... I have never lose the satellite signal and I run mostly in area cover with tree . I turn the forerunner on and then do a a couple of minute worth of strech before I start my run so the forerunner have already located the satellite and be ready to go . I can not imagine run without it and I highly recommend anyone who be into run or biking to get one . the only thing I have a complaint about be that hit the power button to turn the backlight on be a pain ... I wish there be a easier way to turn the backlight on ... I use the backlight regularly since I do most of my run at night .