I've been using my SGS Vibrant for a few weeks now and have had great success with it. I haven't done a lot of modification to it besides rooting to change networks. One of the things I planned to do with it when I purchased it was to use it for GPS data logging during long hikes, and adventure racing / orienteering events of at least 24hrs. I work in the GIS field and have used a number of different devices that are designed specifically for rugged data collection. While a dedicated gps data logger may be more suited I've decided to make this hardware fit this task. Some of my requirements are: -Waterproof -Batteries must last at least 24hrs -Device must stay turned on for the entire time (No swapping batteries that would require a reboot) -Rugged (Survive life in a pack while hiking) -Wifi/Phone/Display are all optional -Data logging of at least every 5mins Some things I've considered: -3500mah battery, ordered and awaiting delivery -External AA or AAA to USB battery pack to charge the phone -Pelican Style Case (Universal PDA, 1015 are good options but wouldn't fit the USB pack. 1050 might be a good option) -Bluetooth GPS is not ideal because it requires another power source to manage. I haven't looked at exactly which software I'd like to use, I haven't looked at alternative roms to save battery or custom data logging software that can turn the gps on and off yet. I wouldn't rule out either of those if they were required. I'm going to start testing a few of these ideas soon. Any suggestions or ideas would be appreciated.