I visited the Beemster polder in April 2024 and April might be the best month to do it as you get to see the stereotypical tulip fields in full bloom and I was also lucky with sunny and warm weather. I think the polder has bit too negative reviews here! Yes, it looks just like anywhere else in the Netherlands but at least I enjoy that landscape. Also, for me the farm houses in the polder looked older than usually so it did have a bit more historical feel to it (or I just imagined it so that the polder would feel more special).
We visited the polder with car but you can get here also with bus from Amsterdam. We drove through the polder starting from north at Avenhorn and driving to south towards Middenbeemster. Besides tulips, the fields were full of birds so also for birdwatchers this is a great place to visit. Unfortunately also many birds had been hit by cars and the road looked like a killing field at points. We stopped for short time at the tiny village of Noordbeemster to take photos of the tulip fields and some of the old charming farm houses (pictured). Next we drove to Middenbeemster, the centre of the polder. Middenbeemster hosts the polder visitor centre which was worth visiting. The visitor centre is kept up by volunteers and had many free brochures about the polder and the surrounding area (I picked up great map of defensive water lines) and they even sell Beemster polder magnets. The centre also has the official WHS plaque inside. Otherwise, Middenbeemster was lovely town to have short walk around and to enjoy ice cream in sunshine, many locals were out too enjoying their Saturday. After our visit in Middenbeemster we drove off to Amsterdam.
I think the polder earns its place on the WH list as I think Dutch polders deserve to be on it and this was the first big polder project. It's not very exciting place to visit but as I do enjoy the Dutch landscape I enjoyed my short visit and could do it again to see at least the tulip fields.