I've been using a Garmin Forerunner 405 with a HRM strap for my runs for years. It gives excellent results in terms of distance and pace. How do I know this? I usually run around a standard 400M track. Since I got the watch last week, I've gone on two runs with my iPhone in my jacket pocket, the Watch on the left wrist and my 405 on my right wrist. The first run was around the track. The distance was about 10% low and the pace (min/mile) varied from 10-25% too high. I figured that this inaccuracy is due to the difference between using cell phone towers and satellites for determine distance. The second run was very disappointing. I started off at a 10-11 minute pace (I'm old) and the watch showed 19-20 minute pace. It would sometimes dip down into the 12 minute range, but then it would return to the higher levels. I thought that it could be due to the timer or the distance being off, but that wasn't the case. How could the timing be correct and the distance be only about 10% off, and the pace be so far off? Anyone else see their pace being way too high (slow)?