>> I'd like to learn more about the empty download for zip and tar.  Were you selecting files from a old (pre-4.x) backup, or a new (4.x) backup?
> They were from a pre-v4 backup

>> How many files did you select?  A couple of individual files, or an entire directory?
> I was viewing the contents of a directory and selected all the individual items in there, ~260 items.

I tried this on an old 3.x backup with tar and it worked for me.  I tried both a relatively small and a large (~2700 top-level files, 30K files total).

I'd like to learn more about how to re-create the empty-tar or empty-zip restore problem.

> As an aside, since v4 will no longer be using so many hard links, my assumption is that backup of the pool to tape via bacula or something else will also be magnitudes easier?

Yes.  But if you upgrade a 3.x installation you will still have hardlinks in the legacy 3.x pool and backups.  In a new 4.x installation you won't have any permanent hardlinks, which makes backing up, replicating or copying the storage vastly easier.