I will probably do this in SSIS. This seems to be the work of ETL. BizTalk may give you better flexibility given the data source in the long run, but if, as you say, it is a web service, this is what can be done in SSIS.
Generally speaking, SSIS = batch process and direct data transfers. BizTalk = Messaging / horizontal messaging requests / responses that may or may not necessarily be synchronized.
But do not take my word for it. Include effort, software costs, if relevant, and the longevity of the process.
source share