We visited Sunbury Plantation as part of a day-long driving tour of the island, and for us the 1 hour stop at Sunbury was sufficient. For people interested in really studying the large array of historical items on display, however, this could be a whole day event.
The interior of the plantation home displays an excellent collection of antique furniture, prints (including some very interesting old maps of Barbados), clothing, silverware and china. The cellars and outbuildings are home to a wide variety of antique kitchen equipment, plantation tools and carriages. There is something for everyone - from unbelievably stifling old clothes to the first mechanical washing machine on Barbados.
The items are displayed in a normal household setting, which gave us an appreciation for how plantation owners lived in Barbados, especially the ways their lifestyle attempted to mimic what their relatives in England enjoyed. Luckily most of the items on display are pretty self-explanatory, since the guides provided a mininal amount of explanation. The "tour" was basically a brief summary of who has previously owned the house and how it came to be restored, and then we were left to wander around on our own.
I recommend visiting Sunbury because it is fairly accessible (while, for instance, St. Nicholas Abbey is quite far north) and the entire home is open for touring. If you are interested in learning about domestic history in Barbados, Sunbury makes an excellent excursion.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC