It'd really be nice if Entune could download trip information -- more detailed than what the in-car display snows -- and allowed us to access it. (Or did I miss something?)
Pretty much true. The only thing I find useful in it is the gas price finder. (And that's because I haven't looked for one for my iPhone.) Sync'ing/Downloading mileage info would add a lot of value to it, for me. I don't want to have to maintain a spreadsheet by hand, plus I imagine there's information in the car that it doesn't necessarily display. In fact, I hope that Entune-3-capable cars will get an upgrade to Car Play. The consensus around here is that won't happen. So I'll have to give that caveat every time someone asks me about the car -- "Love the car, the mileage, the features... except for the poor software and it's the only modern car that doesn't support Car Play." So what should happen is that it goes Car Play, then Entune becomes an app that downloads the Eco diary, etc, from the car to help track things. (I run an app to download data like that from my CPAP, so why not my car?)
When I have a mileage calculation that I want to keep, I take a photo of the screen with my phone and, possibly record notes in the associated info or EXIF file. For example, here are two photos from a recent trip between the Bay Area and Yosemite. The Trip B mileage shows the trip stats, while the diary image shows the daily stats. (The mileages don't quite match because I didn't reset the Trip B calculation until about 6 miles into the trip.)