My background: 34 yrs old, with a good bit of technical knowledge of cell phones and computers. I've owned several types of smartphones (Blackberry Curve, BB Bold, HTC EVO, Samsung Transform, MOTO Q,etc) and used many others. I used this device a lot over three weeks, personal use and corporate use (emails, calendar function, etc)
Phone design: The phone feels good to hold (size), but button placement (touch screen buttons, and physical buttons) is not good. I'm constantly hitting multiple buttons that I don't want to hit. This results in pre-maturely sent emails, txt messages, and calls. This also leads to illumination of the screen when I did not want it.
Overall Performance: This phone is sluggish in the store, sluggish out of the box, and after some tweaking, still slow. The touch screen is slow to respond in just about every application, and even on the home screen, with no apps running. The "pinch to zoom" feature, used within the internet browser is near unusable. It's either fully zoomed in, or fully zoomed out. I tried other browsers (opera mini) and had the same issue. There is also an issue with a couple keys on the keyboard. You'll be typing an email or text message and the phone will suddenly open another email, or open some other application. It's almost like some of the keys are acting as shortcut keys for apps, or the messaging function. This often times makes the phone unusable for messaging of any kind. We were told by sprint that it's a known issue that their working on. We had to restart the phone to get it to work properly.
Calling Function: This is the biggest let-down. Several times a week I've had problems making and receiving calls. Because the screen is so slow to respond to commands, answering an incoming call can be tricky and I only had a 70% success rate at accepting calls.
Facebook and other Apps: I know this is a third party app and can't really be supported by sprint, but this is a necessary application for any smartphone/facebook user. Facebook rarely worked over the 3 week period I had this phone. There were constant errors, etc. I tried uninstalling/reinstalling the application, with no success. Facebook really only worked about 50% of the time. Other apps had problems opening(like weather channel and others). Apps would attempt to load and then close immediately.
Conclusion:
After all the issues with this device a master reset was done, hoping to fix the issues by taking the phone back to factory settings. This did not work. I think this phone has some serious design/software issue, is extremely unpolished, and is not really a device I would recommend to anyone.