Minimal number of files. Your server limits the number of simultaneous downloads to 2 (or 3?) which is reasonable mgmnt of your bandwidth, but the store login typically expires during that time (not a big deal but nice if it was longer). If there are a large number of files, it'll take a much greater amount of work to download them all, keep track of which ones were already d/l'd, etc. And easier management once they're downloaded.
Thanks for asking!