Having done both, I really like the compactness of the van setup. However, it takes more planning and organizing to get everything in an out. Also, not having a vehicle to leave the track if you need to run and get something or go grab food is pretty inconvenient.
The trailer is nicer from the perspective of having dedicated space to work with, and being able to unhook and drive the tow vehicle around if needed. The negatives are then having to have a vehicle that tows well, and it takes up a bunch more space.
In my ideal world, I would have something like a Metris or Sprinter as a dedicated kart hauler. But I have access to space to park my trailer and a vehicle that can tow, so for me, I am sticking with the trailer for now.
Here’s a thread on my quirky vans: