What Should ZipTie's Default Database Be?

The database we use must be open source software (OSS). If we intend to "ship it", it must be under a license that is compatible with MPL 1.1. If we don't intend to, no such restriction exists.

Resources:
http://www.devx.com/dbzone/Article/29480
http://www.polepos.org/
http://weblogs.java.net/blog/davidvc/archive/2007/06/replication_in.html

Things That Concern Me

Apache Derby:
Speed, speed and speed. Unclean shutdown sometimes requires manual restart. No scrollable cursors (do we care? I don't know.). No updatable cursors.

HSQLDB:
No ACID. Issues of corruption during unclean shutdowns, preventing restarts (requiring smoking the DB). Basically, HSQLDB is right out.

MySQL:
We can't ship it. Means an additional install for the user. Also no scrollable cursors. No encrypted database support (Derby and H2 have it).

H2:
Stability. Completely new database from the HSQLDB guy. One guy (H2 Group my ass). It's 1.0. Beware that benchmarks of this database are running with Index logging off. Any serious application would run with it on. Scary caveats: http://www.h2database.com/html/frame.html?faq.html&main

Update (2007/08/10)

The decision has been made to go with Apache Derby for the Kepler release (and possibly Draper). It has proven more robust then we thought, and provides the best out-of-box experience particularly on Windows where a database is not generally present (unlike Linux).