been on this forum since day one and have had the 3D since day one. Have not seen the experience you have noticed. does nto mean it has not happened, just that its not common.
the handset is solid.
it could be anything. if you completed a factory fresh reset and it had the same issues WITHOUT loading up apps, then its a handset issue. if you did the reset and then re loaded the apps and the issue was there, then it could be an app or two. could have been the way you installed them, could have been a bad install, etc.
if the handset is new, why beat your head against a wall? just swap it out for a new unit.
I have merged your post here since you are mainly having rebooting issues. the evo 3D has proven itself to be a worthwhile contender (one of the top 5 handsets of 2011) and is very stable but just like any other mass produced device, it can have some issues crop up here and there.