I depends on what you are trying to achieve. I have been using both for different purposes. The archi-lab node lets you select only certain elements from the link instance. Then in combination with geometry.transform node it works quite well for me (and fast). In case I need a whole category of elements from the link, I would definitely use Bimorph.
I didn’t get the designscript part, what do you mean? What are you trying to achieve? Getting elements’ geometry or solids is actually a quite slow process.