The Citroen Berlingo, Peugeot Expert and Toyota Proace are all the same Van, just badged differently.
I bought the Toyota Proace just over a year ago because Toyota give a 5 year warranty (3 year for the others) and gave me a great deal on the price and threw in a few extras too.
Mine is the Compact version, 1000kg payload (more than enough for my 700ltr system).
Absolutely fantastic van, can’t fault it at all. I was sceptical about the (what I considered) smaller engine, but don’t be put off, it has plenty of power even with a full tank and 3 people in the front. (It has 3 front seats)
I have a 700 litre Pure2o system (ionics budget range) and that is also highly recommended. Worked perfectly every single time, and with the smart charge system the battery is always full.
I had a 400 litre system in a VW Caddy before this, also a great van but I wonder how I got by for so long with just that small system.