I spent 3+ hours there (and this is not the Louvre!). Visitor can focus, go through slow or fast -- and during my visit, things were pretty quiet there (this is January).
Visitor enters historic building on a quiet cross-street (purpose-built orphanage then pensioner home in early years) . The building alone is fascinating and you can see elements of both histories during your trip through 20-some spaces where the art is displayed: floors, dining room, windows, fireplaces, detailing, artifacts.
Museum visit is well-arranged and quite informative. You learn a lot about Frans Hals, as well as his era and the (largely Haarlem-based) artists who built on his work. You'll see a smattering of paintings by Hals and scattered paintings by others in all sorts of museums -- but not the focused display you see here. And the paintings are in a very helpful context that lets you really understand Hals a lot more deeply.
I will never look at a Frans Hals painting the same way I did before (cheerful, captures emotions, splashy for the era). Based on today's visit, in a smallish museum dedicated to this artist, I have reframed (!). Here you have a genius of a painter (a long-lived one and productive at that!) woven deeply into his community, taking on the task of documenting the various companies responsible for civic safety in Haarlem (through his paintings) -- and also doing portraits of his various sponsors, family members (he had 14 children), and others. He had a tremendous following of very prominent artists, some of whose work is also shown there.
The exhibits are accessibly organized and informative: the Dutch descriptions of the art have English translations right next to the paintings -- and there is a lot attention to allegory, historical information, contemporary response, etc.
Admittedly, I occasionally get drowsy in an art museum; not the case here.
There is a pleasant little cafe there tho not the gourmet level that you'd try build into your day if you didn't stop by there for convenience. The ancient building is on a quite charming side street and has a beautiful courtyard such as you'd find in a monastery.
To avoid being upended: Make sure you keep an eye out for the bicycle traffic on the narrow street!
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.