I’ve had 2 DBP Golfs (a mk4 and a mk5). Owning a black car is a labour of love, but as you had a black mk4 Golf, you’ll already be aware of that.
A good washing and drying technique will help to keep paintwork swirls at bay, but over time, even with a careful washing and drying regime, eventually you will get some swirling.
DBP looks fantastic if you’re prepared to put in the time and effort to keep it looking good. If not, then a lighter colour that doesn’t show swirls might be a better option. Would I have another black car? Yes, because I enjoy cleaning and detailing my car. However, if it was a choice between DBP and Indium Grey, I’d probably choose Indium, but only because I’ve owned more black cars than any other colour.
If you do decide on DBP, what ever you do, don’t let the dealer wash your car!