New van?
Don't know i've done both.
Bought a ducato for 2k owned it seven years spent 5k on new engine and gearbox before scrapping it.Got tired of fixing it and chasing mechanics.
Next van ducato brand new 11k.Owned for nine years no money spent sold for 1k with 35 k on the clock.
Next van when i started wc s/hand scudo 8k 3yrs old. No problems, changed because i wanted a bigger payload.
I'm useless at buying and selling vans and have no interest.I have tried on the internet but it's a lot of driving about to look at junk.
New vans do allow you to get on with your business, not even an mot for three years.They also make you feel good about your work which i think is also important.There are enought things stopping you going out the door as it is without negative feelings towards your vehicle.
Most decisions feel like big ones at the time, but when you look back they were details, and you would have done well no matter which you had chosen.