most 'accurate' cycling app?

[onsight512]

are any of the cycling apps 'super accurate' when it comes to grades?

i've been using strava and while it seems relatively accurate, i wonder if there's anything better. i tried velopal today (first time)on a route i've ridden before and while it seems like a nice app, the grade info was wildly inaccurate. at one point it shows a 181% grade. strava shows a 29% grade in the same place and i think that's also way off. i can't imagine it's more than 10 or 15%.

strava:

https://www.strava.com/activities/61...5f0dfe9036fad8


velopal:

http://velopal.com/activity/913226.html

[Cicli]

I have been using Velopal. I dont really have grades here though. Well, a few passes over the highway if those count.
I rode 50 miles and velopal had me at 800 feet of climbing. Awesome.