I would be happy to beta test. As others have said, the Gas Tracker+ app is only available to US users so no one outside of the US can provide any feedback on current functionality. Not sure if you plan on changing that before you do the next release but it would be terrific if you do.
I just started using Fuelly and the mobile browser works well, but apps would be great! I am looking forward to the Apple app (for my wife), but also an Android app (for me). Hopefully they will both be available in the future.
I've been using the GasTracker app for a month or two and have been quite happy with it. I'm currently tracking my car, truck, and two motorcycles. I have two issues to report, however:
1. an offline option would be nice. Over the 3G network, it can take a while for the app to initialize and allow me to input a new fuel-up. I can't imagine what will happen when I'm roaming.
2. I just traded in my truck for a newer one. I liked the ability to retire my old truck. However, after inputting my first fuel-up for the new truck, the app continuously crashes, but only if I attempt to view the new truck. This is quite inconvenient. The car and motorcycle fuel-ups work just fine.
Also, I've had an issue where the big + button on the GasTracker app results in an error message, "You must add a vehicle before adding a fuel up", even though I already have a vehicle in my garage. (I can add a fuel-up after going to Garage > [my vehicle] > + button.) Any known solutions to this issue?