Best Palace

We were pleasantly surprised by Sans Souci. It was much smaller and intimate than other palaces we have visited and it was pretty inside. It didn't take long to tour the inside of the palace. I didn't really care for the interior of Versailles but did like San Souci. Frederick the Great threw a lot of parties there and he is buried near the vineyards along with his dogs. The Queen's summer residence is across the property. The whole park is a nice place to go for a walk.

"Best" is obviously a matter of taste and preferences.

As mentioned by OP visitors have to decide between castles and palaces - different building types with different purposes.

I prefer buildings with a historical relevance and a puristic architecture. One of my favaorites is one that you did not mention: the palace Neues Palais in Potsdam. While Sanssouci had no histrical relevance at all, the Neues Palais was a "side office" for kings and emperors, also very much liked by last Prussian emperor Wilhelm II.

Not a castle but a fascinating one to me is red fortress Zitadelle Spandau in Berlin - a masterpiece of defense.

What I really dislike is the architecture style of the New Berlin Palace which you will automatically see when you visit eastern center of Berlin. It is really a new built complex with a mixture of the original destroyed palace and new office building elements. The fully inelegant design to combine the two very different architectue styles is too hard to see for me.

Keep in mind the palaces/chateaux in Potsdam do not limit themselves to only Sans Souci. The are numerous others as well, such Neues Palais, which historically is mor important than Sans Souci. In Potsdam Hbf is the Tourist Office, which sells postcards on Potsdam, two of which focus of the several Potsdamer Schlösser. The title of one card is " Potsdams Schlösser"

If you have the time pertaining to Berlin, I would recommend also Schloss Köpenick, Schloss Charlottenburg, Bellevue.

I went to see the Köpenick district (mainly the Rathaus ) in 1999 only to see that the Schloss then was undergoing refurbishing, etc, saw the Schloss last summer from the across the street, all refurbished, etc.

@ MarkK..."...very much liked by the last Prussian emperor...." I know you mean, "Prussian King, German Emperor" referring to Wilhelm II, (preußischer König, Deutscher Kaiser), as he was constitutionally.

@Fred, ... yep, fully correct in the official way. I just wanted to shorten that he was the last emperor from Prussian ancestry (Hohenzollern) :-) We had discussion on him before in a different thread.

I've been to Nymphenburg twice and enjoyed it. I was at the Würzburg Residenz and was not impressed. Just an overly gaudy palace for a religious leader. I also did the Marienburg Fortress in Würzburg and enjoyed it much more than the Residenz.

Residenz and Nymphenburg. in Munich are very different, so why not both?

Since you liked Versailles, consider Herrincheimsee where Mad King Ludwig was well underway at outdoing Versailles when he was murdered.

Near Fussen, there is a collection of impressive buildings-- Weis Church, Linderhoff Palace, Neuschmanstein Castle which is really a palace, and Hoenschwnagau.Palace (spelling not assured).

There is a good Baroque Palace just S of Cologne.

I've always like the Baroque Palace at Mannheim. Not as spectacular as some, but the largest palace in Germany

And for history, the Emperor Constantine ruled the Roman Empire from his palace at Trier, the oldest city in Germany. All that's left is the Throne Room, which is today the largest church in the city

I enjoyed Sanssouci the most.... not Sanssouci the palace, but the whole park. The main palace, which is small and intimate and illustrates the "Prussian virtues" of the king (just like the very plain last resting place of Frederick II., with the dogs and potatoes as nice details), the New Palace as Fredericks fanfaronade to show the world that Prussia was still mighty after the Seven Years War (including the very picturesque Communs behind the palace), the very modest neoclassical Charlottenhof, which perfectly illustrates 19th century Prussia, just as the Roman Baths, which are a product of the German Italiensehnsucht (longing for Italy).

We are interested in history and especially in sights where a visitor
can feel a connection with those from the past.

In this case Sanssouci is the perfect place, since almost all of these buildings weren't built to impress, but as hideaways of the royals during the summer. They reflect the taste of their owners.

I really enjoyed Sans Soucci and the park. Have been twice and wouldn't mind going again. Just the entire concept of this place is a bit mind-blowing and the palace interiors are fantastic too. Whether you stop at the windmills, the Chinese Tea House, the church or the palaces, you will be in for a treat.