This is a phenomenal app, providing a glimpse to the holy grail — a fully integrated bike computer / app that makes your smartphone the only device you need. I currently roll on most rides with an ipod, an iphone, and a garmin bike computer. Really, I could do it all with the iPhone, but there are some trade-offs which we’ll touch on below.
I use Strava for iPhone when my Garmin battery dies — otherwise my standard program is uploading files from Garmin to desktop to Strava . . . but this is because I care about the power data for WKO desktop. This is more and more an edge case even for the most geeky of power / wattage cats, as Strava and/or Training Peaks will provide all you need in the cloud/web service. But it is not there yet. However for 99% of cyclists WKO desktop isn’t needed, and you can actually capture full heartrate and power/other data using the Strava app and iPhone after market sensors for Ant+ and the built in bluetooth, sick!
Just to niggle a little, another tradeoff is the footprint of an iPhone is pretty big compared to a Garmin (even the 800), and mounting that big ol smartphone thing on your bars is not that sweet, and then of course you crash in a race or run into a tree on your mt bike or whatever and your smartphone implodes. You could roll a standard computer up front on the bars, w/ the phone in your jersey pocket doing the Strava thing — however if you are using HR strap there can be issues with the signal if the phone is in the back . . . see? Still some kinks in the holy grail program. But I am niggling and begging for the grail, of course. Maybe the holy grail lets me insert my smartphone into my stem — clip in style and protected, and of course the battery is charged by the mad watts I am putting into the cranks. Give it a few years :)
The other obvious trade-offs here are you need to roll your GPS on — which can hammer battery life, especially on Android devices.
The bottom line is the Strava app for smartphones is amazing and deservedly award winning — below are links to many of the reviews and further resources: