if you be interested in the GPS aspect of the device , you can read the other review -- like they nearly all say , the 205 and 305 be excellent . I want to specifically point out how much improve and how accurate the heart rate monitor and strap be over the previous version -lrb- forerunner 301 -rrb- , as well as how favorably the 305 hrm function in comparison to the benchmark Polar monitor . the 305 have not drop my heart rate once in nearly three week of daily workout range from one to two hour . I have and have use the 301 for the better part of a year , and continually have problem with interference , which cause extend datum dropout and extremely high , inaccurate reading . the 305 be nothing like the old 301 , which be reason enough to purchase if you require a solid hrm with you gp datum . a side benefit -- it be accurate ! I have compare it with my Polar Accurex monitor , and it be dead on . if anything , the Polar update a bit slower than the Garmin . all in all , a huge improvement , and a great product . highly recommend . also , as a number of other reviewer have say , get the SportTracks software . it be free and it will greatly enhance the viewing of the datum from you new ForeRunner 305 .