I don't understand the need for a bike GPS. I use a simple Bell F-12 to track MPH and ave MPH and distance. All of my rides are planned on MapMyRide. I want to know how far and where I am going BEFORE I ride. Also, I want to know the vert ft/mile ascent so I know how hard it will be. I have a lot of hills to deal with here. Having a GPS only gives me those numbers after the ride. I don't hop on my bike and ride randomly. Now the speedometer and the MapMyRide miles are off by a few percent, but i use my bike computer because i figure MMR is for a straight line ride.
Now some of my miles are complicated on country roads, so I take a simple screen shot of the turns and paste them to a page and throw the page in my pocket. Most of the time i don't want to stop to even look at the paper for tricky turns, let alone screwing around with some bike computer.
Also, I keep a spreadsheet of all my ride, and keep total miles by week and month and grand total. It's all custom. The ft ascent/mi is all right there, so I can compare my similar rides and check my progress. Then i have about 7 rides that are my main rides, where i keep the Personal Best records on those rides. To have all this stuff The Way I Want It on a web site is not going to happen.
Also, I put the phone in my bag, but certainly don't want to be screwing around w/ it on a ride. The only negative is that my Bell F-12 always shows the MPH, i wish I could make it go blank sometimes and just focus on the ride. I really care about ave speed at end of ride, usually I don't look at that screen until I'm done. I out "there" to ride, not to be screwing with gizmos and worrying about number, I only want to think about shifting right and keeping right cadence to conserve my energy.