If it helps I can give you the numbers on the Vivaro I bought.
Last of the old shape bought in July 2014. Air con, bluetooth, electric this that and the other. £11k plus VAT, paid the VAT and traded in my old van as deposit. As I'm VAT registered the VAT was claimed straight back that quarter. £221 pcm for five years = £13,260. Two years on and it's done a shave over 30,000 miles. Service at 25,000 cost £250 at the main dealer. Other than fuel and tax I paid £160 for the sign writing, and £425 for a new Rhino roof rack and £100 on birch ply to make the racking. At some point I'll get a split charge and leisure battery set up so that I can charge drill batteries etc on the move.
I look after it, but inevitably it's picked up a couple of small dings and stone chips. I would class tham as normal wear and tear for that age and mileage, but a lease company would take a different view. All the payments and running costs are deductible so comes off the top line before tax. Vans in the same condition and age are currently selling for @ £9k so it's depreciated by one year's payments in two years.
The van is mine when it's paid for, and shows as an asset on the company's books making the company look healthier without adding anything to the liabilities.
I can trade it in for a new one if I want to, or alternatively I can just keep running it.
When I looked at buying a van and ran the numbers I just couldn't find a better deal or way of doing it. I certainly wasn't going to spend an extra £8k for the same spec and size van from Ford, or an extra £12k for one of Hitler's finest.
The depreciation argument doesn't add up when you look at the figures, and there's no additional benefits to justify the additional cost.