ok, its almost 5 years since the above posting and all I can say is: jsch rocks! I've tried all the other java implementations of OpenSSH client and this one is by far the best.
I must also note that I've had a good experience with jsch. There's a bug that causes a session connecting with an incorrect password to endlessly try reconnects, which causes some SFTP servers to lock down the account for too many failures (fixed by shoe54 http://sourceforge.net/project/showfiles.php?group_id=215436\). However, I tried jta and a few other libraries, looking for SFTP functionality, and jsch wins out hands-down. Perhaps it's just my skill level, but I found jsch to be MUCH easier to use than any other library I tried, and the jcraft.com jsch page has a number of examples for various operations that helped.
Regardless of a few bugs, my kudos to the author of jsch for his work and for making it freely available.