Hard to say in case I am wrong, Coromal, Roadstar are good vans. I know Billabong make good vans but I am sure I am missing mentioning other great manufacturers. I don't own a van but things to look out for are things like - are the cuboard hinges full lenght aka piano hinges, or are they normal hinges like held by 6 or 8 screws per hinge A Billabong salesman showed me this.
If you google swagman forum, they will point you in the right direction. Just remember like aircraft, everything is built to a price point. As mentioned above ELITE build Imo great vans here in oz. But they cost a ship load.