My unit (and probably many of yours out there) has a power issue.
SAMSUNG - Acknowledge the power issue. Best Buy "Fixed it" or rather took it in upgraded the firmware to fix the power issue and sent it back with the same exact problem.
PROBLEM REPRODUCTION: You press the power button to turn on your unit for 2 or 3 seconds, nothing happens. Now plug in your charger. If you don't see the battery icon (the big green charging icon on the screen, then your tablet has the issue. You have to Hard start it by holding the power button down for 12 seconds. This will restart the unit. Then you will see that the battery icon comes up. Now you can do a normal start with instant on.
This problem happens in 10 min of non-use, in 20 min, in an hour, but it at some point always happens. The battery is still with power, but the unit constantly (most times) needs to be hard restarted rather than just coming right on.
I am going to contact Samsung for them to fix it this time (Best Buy isn't exactly competent or trustworthy on these issues - and for a store with sky high prices they aren't exactly rated highly on customer support or service).
If you have this problem - please feedback some info and lets get Samsung to fix this issue or do a recall. Best buy sure doesn't give a crap!