The 1.9 diesel engines are very slow.......but the engine will do 150,000 miles and more.
The 1.6 hdi turbo diesel engines give much better performance but I believe some of the older hdi models can suffer from electrical problems. Regular oil changes are recommended particularly for the hdi engines.
So look for service history that shows regular periodic servicing has been carried out.
I personally think they are good vans. I previously had a 2005 1.9d Berlingo and have now got a 2013 1.6 hdi Partner.
The new one is great.