I don't have direct experience, only from probably too much online research.. We're going with Sportsmobile for our build and moving from a Sprinter to a Transit for the Gas engine.
For a production van, the PleasureWay seems to universally get high marks for quality. I just drove an Ontour 2.2 yesterday and the internal quality looks great. Can't tell how the wiring is done, but their videos and customers say it's good.
I'm going with Sportsmobile because their quality seems to be excellent and I can get exactly what I want (the Pleasureway has some build choices I don't care for) AND it costs about $15-20k less than the comparable Pleasureway