For those of you who track such things, which data do you "trust" the most? I went for a little 25 miler today and just uploaded from my Garmin Edge 305 and here's what various software programs come up with for elevation gain:

Garmin Training Center: 2099'
Ascent: 1748'
Garmin Connect (online): 1984' or 2887' with elevation correction enabled

I forgot what the unit actually said on the screen before I uploaded it (and elevation gain isn't kept in the history apparently), but I wouldn't be surprised if was yet another different number.

On the one hand, I'd think that the elevation correction enabled should be most accurate in this area since there ought to be plenty of real gps data for the software to use to put real numbers on the route. But it just seems way too much compared to the others and so I'd toss it out just because it's so far off.

So what's the deal with this stuff?