tape as an archival medium

Hi all,

I used tapes aplenty back in the 1990's. They were a relatively cheap
way to save your data; obviously, slow if you had to access it. And
after 2-3 years they would usually go flaky (I am talking 4mm and 8mm
tapes).

Now I am wondering if anybody has had any recent experience with them
and what they impression is. We are potentially looking to archive up
to 20 TB of data (for now).

Any reports of experience, both positive and negative, would be
greatly appreciated.

Boris.