Ive never have had a reboot issue and never been on C but from seeing what others have said C was just crap and didnt fix anything. From what Ive seen D has been more promising.

 

Yeah I happen to never get rebooting issues at all. Maybe once a month. Also on B. Didn't wanna bother going to C. Customers have been complaining to be that C has been doing the same thing. I did have a customer upgrade from A staright to D and it fixed the random reboot problem. Otherwise if it persists, Corporate should be getting more Esteems soon because they've been backordered for a while I even thought it was EOL but it wasn't lol

 

they say it fixed the rebooting but i never had rebooting problems. I updated just for shits and giggles

 

My Esteem used to reboot around 3 times a day when it was on B. Didn't bother with C, but updated to D a few weeks ago and haven't had a single reboot since.

Edit- It also improved the hell out of my battery life. I used to have to carry a second battery on me and switch it out literally after 4 hours off the charger. Now I don't even need the second battery at all as my phone lasts all day. I still carry the second battery just in case, though.