I use the Garmin 305 to go trail run in area where tree branch cover the trail 80 % or so , and the new GPS chip in the 305 do a good job of tracking . the software problem that cause the original delay in the unit shipping apparently be not fully solve ; I have already download one firmware update from Garmin . elevation change be not track as accurately as they could be when use the desktop software that ship with the Garmin , but when upload my result to the free www.motionbased.com site -lrb- recently purchase by Garmin -rrb- , the elevation-related statistics become much more accurate when use the ` auto-correct ' and ` gravity ' feature of motionbased . E.g. , on a recent long run , Garmin 's desktop TrainingCenter say I gain and lose 2,800 foot of elevation but motionbased take the same raw datum and say I only gain and lose 1,800 foot -lrb- much closer to reality -rrb- . the calorie metric produce by the unit be also WAY off , but this appear to be a known issue per various website and I suspect a software\/firmware update will fix it later . otherwise , the desktop software and free motionbased.com site be awesome and I love the unit . highly recommend .