Hmm, I'm pretty much set on getting a Garmin due to this very issue. At least I expect it to be relatively close to accurate in comparison to the online tools currently available. I just did two days of Ragbrai last week that showed roughly 2000' of elevation gain per 70 mile day per the route maps provided by the organizer and was a bit concerned since my typical training rides mapped on Routeslip are showing about 800-900' over 45-65 miles and my hardest ride this year only mapped at 1800' over 75 miles. The Ragbrai days were basically a joke compared to what I have been riding for training. I flew through those two days in great shape. Just to be certain I wasn't just remembering my 75 miler being extra hard due to it being 6 weeks ago, I rode it again today and it was still tough, just slightly easier now that I've got an extra 1000 miles on my legs.

I'll probably be ordering my GPS this week and will try to get some comparisons done over the next month.

Rick