Had a 4+ hours delay from New York to Germany with a United flight. United offers us a $100 voucher per person. Accept or not enough?

For a 4 hr delay at Newark, $100 is fine. That's $25 bucks an hour, which is thoroughly sufficient. Unless you missed something in Germany like a cruise or a wedding, you should accept it. Be glad you flew United, some airlines don't even apologize for delays.

Take it had 6 hrs in Bangkok and Offered Nothing Airlines are Not required to offer you anything for short delays

Pity it wasn't the other direction, or an EU carrier, you would have been entitled to EUR 600...!

Still, better than nothing. Take it. (Although before taking it, ask them if that's their final offer... Or ask if they'd give you vouchers worth more, they might do.)

I would accept it if I were you.

I actually don't mind a few hours delay. Gives me more time to roam around the airside of the airport and take pictures of airplanes. :)

I think it is pretty good since I have had delays and the airline offers no compensation.

It's not a negotiation. Either accept it or stop complaining

You may as well accept it. You will go through much grief trying to get more and you may not be successful.