Hi Guys:

Yes, Berlin is worth doing.
There is lots of history there (duh!)
& some wonderful museums.
Walking tours are very good & reasonable.
The Radisson hotel is a very nice one. We had a couple of good meals in the restaurants there.

But, be aware that not all Germans love Americans. In all of our travels, the trip to Berlin is the only one (& we have been to other parts of Germany) where we were insulted because we were American.
It is not a big deal & won't happen to you (I would guess), but there is an undercurrent.

That being said, I would still go back.

Best, Doug