We did Newcastle to Amsterdam in March, in a dog friendly cabin which was great. But, when we docked they couldn’t raise the mezzanine deck so it took 90 minutes before we got off - that was just unfortunate and not something likely to repeat, of course.
Next, police checks, and customs checks - done separately. There was an empty van in front of us (apparently going over to bring stuff back) who was opened up and thoroughly checked by police; 20 meters further on customs did exactly the same thing. So because everything was being duplicated, another big delay.
We got asked by customs whether we had any knives (erm, yes, there’s the cutlery drawer …) so they had a good look at that. Fortunately they didn’t look for dog food
(get us, like an international smuggling ring).
Then, they asked how long we were staying in the Netherlands. We didn’t know whether it would be one night or two, so we said we weren’t sure. The officer said in that case, as we hadn’t booked our return crossing, he had to assume we would be there for the full 90 days we were allowed, which is fair enough. But there is a sum per head per night and he demanded I show him my banking app to prove we had that amount. I thought that was a bit excessive.
I would use the crossing if we were going North from Amsterdam (we were going into France and Spain), but the miles we saved on this side weren’t offset enough by the ones we had to do on the other side. And I’d say we were staying for three nights.