I've had the same experiences with the Backtrack Point 3 that reviewer "hunter" describes- wildly inaccurate readings, commonly 90 degrees and occasionally 180 degrees off target. The only other Amazon reviewer, "Terry", makes no mention of this problem and gives the unit 5 stars, but I note that Terry is from Overland Park, KS, the home of Bushnell Corporation.
The problem is that the digital compass must be re-calibrated very frequently. Recalibration is mentioned near the end of the instructions when describing compass mode, an option not likely to be used by many purchasers of this product and thus often not read. Bushnell does not warn users upfront of the unreliability of the compass arrow pointer and its need for frequent recalibration. Any GPS-type unit this unreliable should NEVER be used alone for guidance in unfamiliar wilderness areas or other critical situations.
According to the instructions, when you're ready to leave your car or other start point you simply power up the unit, hold the Mark button down until the Distance To Location changes to zero, then turn the unit off and go. When ready to return to your marked start-point you just power up and follow the arrow.
WARNING: Don't head off immediately in the direction of the arrow, as it can be 90 or more degrees off-target and can remain that way even after you travel some distance, especially if you are moving in a straight line. Recalibrate first by rotating the unit in a figure 8 motion several times, pointing in all directions and walk in a circle. (Bushnell has a demo video on their website.) At that point you have a good chance of being roughly on target, but keep checking the Distance To Location number (which seems accurate) to make sure it is decreasing and you are moving closer to your target. The arrow can drift and point far off-target while you are moving in a straight line, so re-calibrate often.
The unit can also be slow to lock into satellites in new locations, especially in wooded areas. I'm not sure how it would respond in the canyons of a large city. The Backtrack Point 3 is hyped as "GPS made simple". It is, more or less, but it poses an unreasonably high risk of giving large direction errors that may sometimes lead to serious consequences.