I visited Esztergom and its castle in November of 2024 on a day trip from Budapest by car. The direct driving distance between Budapest and Esztergom is a little bit over an hour, and most auto-enabled people will combine the visit here with at least one other place. In my case, I drove to Pannonhalma in the morning and then spent most of the afternoon in Esztergom.
Esztergom Castle is located next to the Esztergom Basilica at the highest point in town. The part of the description related to the castle emphasizes its medieval architecture and artistic value, as well as the influence of the Italian Renaissance. A casual castle explorer will find features of note here or there, with a number of passages, chambers, and vaulted ceilings that reasonably impress. But it is hard to call anything here truly outstanding. It's a nice castle. I've seen better.
Small expositions, ranging from kitchenware to weaponry to crown and episcopal jewels, provide an additional measure of interest. The most impressive part of the castle may be its views from several terraces and elevated rooms, taking in the dome of the basilica, the banks of the Danube, the bridge connecting Esztergom with the Slovak town of Štúrovo on the other side of the river, as well as the rest of the town in the opposite direction.
Because I had a couple of other targets to explore in Esztergom - most notably, crossing the national borders on foot by walking across the Mária Valéria Bridge to Štúrovo and back - I ran out of daylight to visit Visegrád on the same day and could not fit it into my itinerary anymore. My pre-trip research suggested that the royal palace in Visegrád exhibits a bit more overall interest than the castle in Esztergom. However, if I am interpreting the history correctly, Esztergom Castle was added to this tentative submission specifically to improve its value beyond what the Visegrád palace and royal hunting grounds could offer. On my limited evidence, the combined property is still not cutting it in terms of being worthy of the WH recognition.
In any case, I suspect that if I had time for Visegrád, I would prioritize its castle - which is not listed on any existing or tentative WH properties - over the royal palace, for what I heard are amazing views of the Danube Bend.