Wouldn't the S10 have been a good race watch as well? I have been running at least 8-9 marathons with normal series watches - all the way from S0 (with iPhone in belt because it was without GPS) to the S2, S4, S7 and Ultra 1 - my race on Sunday with the Ultra 3 was a bit weird though - My second run with the Ultra 3 with the short shakeout run Saturday morning of 5K the first. Marathon distance was WAY off though, so hope it was just some initial calibration of the watch or something was off. Have read many saying the same thing, but weird with over 43,15 KM (a full kilometer too long is quite a lot)