Power button sleep mode issues

I'm on my second Galaxy in as many weeks and likely will have to return this one for a third.  The issue is that sometimes the Galaxy will not awake from sleep mode (i.e. via pressing the power button) and is just dead.  The only thing that clears the issue is to pull the battery and a cold reboot.  This does not appear to be an Android issue as no other Android phones appear to be suffering from this issue.  Samsung tech support has had me do a complete factory reset and still the problem persists (sometimes once a day, sometimes 3 times a day -- all at random times).  I have no strange apps running in the background during sleep mode.

Samsung refuses to look into the problem other than to say "go get another phone".  Has anyone else experienced problems like this?  This problem is a real trouble as how can the phone be relied upon if it can't stay running?

Any advice would be most welcome.

The Samsung technical support person told me to uncheck the "Power Saving Mode" setting under "Sound and Display".  Unfortunately, his english was so bad that I could not understand the reason why.  We'll see if this works.

I actually installed APNdroid and turn off my data at work. I still get text messages and calls but all that other updating isn't that important to me while at work. Once I did that, my phone never froze. My work site has so much interference that it's difficult to get FM stations. Add in a powerful WiFi extender and you're pretty well doomed.