I never used BT with any other phone, i just remember when i reviewed a few of them alot of people were getting issues with one phone, and not with another. I checked the box for mine and its a 520 like i thought. I use it from 7am till about noon when it gets low then i throw it back on around 1 after it charges and use it till i pass out around 2am. Never a complaint. I use it 99% of the time because im always walking, working, driving, typing, something.
And imo its pretty darn comfortable. Certainly holds up well. I chased and tackled a skip in a liquor store parking lot last tues and it fell out. My boss stepped on it running behind me, barely even scratched the thing.
