Going from SSIS to SAP Business data objects

Someone who knows (not just a copy/paste of widely known very generically stated differences in product description, nor what the 'fans' of each individual product believe about theirs), but someone who is familiar with doing the switch or watching someone do it:

what is it like going from SSIS developer to SAP business data objects , as far as ETL?
assume still on SQL server back end.

similarities? struggles/disappointments? challenges? learning curves?