Because of a prestashop bug, attempting to update the last product of a category that has been sorted in admin results in an ISE (500). Since the webservice rejects the value it provided itself we should try to either remove the position_in_category field (not sure if it will work) or set it to zero (which would overwrite existing position but is more acceptable than an ISE)
When a picture is modified on ABS side, it is not pushed on prestashop, except if no picture exists on remote end.
Should be easy to fix now that we can fetch remote picture (but this implies a lot of traffic so it may be controlled by an option)
if customer is a company, export it as a company (with gender neutral -> to be added on PS first install) and put its contact partners in the address section of PS
Each entity that could be exported to Prestashop should have a prestashop_updated_on attribute which is filled with the last time it has been exported. All select queries should have a (prestashopUpdatedOn is NULL OR prestashopUpdatedOn < updatedOn) instead of using last batch time (which means almost nothing.