Originally Posted by ArchangelPaladin
... including the GW “How to paint…” book say to assemble the whole model first....
Many of the painting articles on the GW website do suggest sub-assemblies for complex models.
I have tried both recently: my Chaos Knights were painted in pieces then assembled and my Marauders were assembled then painted. My experience was that you can assemble then paint but you need a thin brush and good hand control to paint into the depths.
My only problem with not assembling completely was caused by a conversion turning out to be unbalanced when I put it together, so if you are making a special model dry-fitting the pieces is probably a good idea.
Given the choice, I will probably keep with sub assemblies for most models unless I need to green stuff gaps.