I am typing this from not so sunny Den Haag, so will give my experiences. Please note that it is not my intention to settle down here so that will also have a bearing on my experiences. As always, YMMV.
Den Haag is in the province of Zuid Holland, but it is considered the northern parts of the country. It is also not a big city, we would consider this a town in the SA context. Den Haag is probably the most international of Dutch cities, due to the number of embassies and international organizations that are based here. It's nice having a beach, but there are very few days a South African would consider a beach day. 20 degrees is still winter weather as far as I am concerned!
Moving abroad is not easy, and especially to a place like NL which is the opposite side of the cultural spectrum from SA - South Africans are warm and friendly people, whereas the Dutch are not. It is not the directness (It took me a few months to get used to that), but just the air they carry themselves with.
The country is an expensive place to live, rent makes up about 70% of my monthly expenses. Food and other goods are reasonably priced for salaries. A note on rental in DH, a by-law was recently passed that states if you earn more than a certain threshold, you cannot rent properties on the lower end of the market. Properties also work differently here, an example will be that you are expected to install and remove your own floors in a rental.
Getting a permanent work contract is not easy, the company I work for does not give permanent contracts immediately (especially to foreigners). You will need to work for at least a year before you are offered a perm contract. I know of South Africans who are living here for 3+ years, working for the same organization, who do not have perm contracts.
The water from the tap is absolutely **** there. It is hard water which I've never had to deal with even in JHB. I do not drink the tap water because of all the chemicals. You will need to wipe down everything to avoid staining from the water.
The 30% tax ruling is great, especially for someone like me who is only planning to stay for a few years. If you are planning to stay permanently, it is also great but you do get reduced benefits in the long run.
You will have to do TB tests for the every 6 months for the first 2 years that you are here as you come from a high-risk TB country.
Almost everyone speaks English here, to various degrees of proficiency. You do not need to know Dutch to survive, although it will make your life a lot easier if you do know it.
In terms of food, you get good quality fruits and vegetables (I don't know about meat). Dutch food is very very bad though. For such rich people, they truly eat like beggars with their cheese sandwiches (boterhams) and orange juice. This for me is probably the most disappointing part of the Dutch. Luckily there is a variety of other foods to try, but all are imported from abroad.
The weather is very bad by SA standards, and the Dutch love to complain about it. There are more cloudy/rainy days than sunny days. The late sunsets/early sunrises in summer are also terrible for me, it really affects my sleeping patterns as I need it to be dark for a few hours before I can sleep. In winter it is the complete opposite, with late sunrises and early sunsets. This leads a lot of people
Speaking of complaining, the Dutch complain ALOT! and about everything. I find it extremely annoying that they cannot see positives in all the things they complain about (like the trains). I am not a complainer by nature so that makes it even worse.
If you come here expecting the Dutch to be open-minded, you will be disappointed. You will be expected to change and adapt to the Dutch way of doing things if you stay for a long period of time.
At work, I find it very frustrating to work with the Dutch. I find them to be very lazy and slow with tasks, and things must be discussed to the nth degree before work can proceed. This can be just the organisation I work for, I have no idea.
If you have any specific questions, feel free to drop a PM or leave a message here.