Get a Skinomi screen protector. I thought GadgetGuard was the best until I got a Skinomi TechSkin for my Nexus 4. Just ordered one for my new 521 from HSN.
My mom had a 710 from Tmobile. She washed it with a pair of pants, and got a Samsung android phone at Walmart for 200$ last month. She HATES the Samsung, so much so she instantly purchased the 521 when I sent her a link to HSN's deal. It arrived today!
I also had a problem with the battery cover. The lable on the back of the phone shows you pushing your thumb into the back middle of the phone. This did not work, but I was able to get the back cover off other ways. I noticed that the battery is located in the back middle, were your placing your thumb, but its a hollow area!!! THIS WONT WORK WITHOUT THE BATTERY!!!! HUGE error, and someone should be fired. Once the battery in, the instructions work just fine.
Speedy little sucker, and I was surprised to see the screen respond when I was cleaning the face with a cloth!
Biggest gripe so far is the screen itself feels "sticky". With my HTC HD2 and 8X, my fingers just slide on the surface with little to no friction. The 521 has a LOT of friction, and attracts finger prints like crazy.

