Hi,

while some ait critical points are still true,
there are already ait-3 tape devices available,
making your performance/footprint comparisions an aplle/orange compare.
There is some roadmap as well.

Well, end of the year there will be new lto on the market, and so on..

For now, you may want to have a look at:
http://www.aittape.com/ait3.html

Not sure about ait-3 certification with TSM or vice-versa,
maybe only native OS driver support available yet?
Something to be checked as well.

regards
juraj