They are not tough at all, in fact they are tender and juicy with a meaty consistency much like roma tomatoes.

I live in a rain forest type area of the pacific northwest (usa) and they preform as Burpee says they should. I did grow them when I lived in the desert of NM also with the same results.

Here is some info from Burpee about them:

http://www.burpee.com/vegetables/tomatoes/tomato-burpees-long-keeper-prod000978.html