Concurrent use of A2000 and A2003

Has anyone had any experience with concurrent (multi-user) use of an
A2000 front end and an A2003 front end on the same linked set of
tables?

The reason I'm asking is that we've got a number of sites using
A2000(SR1) runtimes on each machine at the site, but, for Vista
compatability, we're planning to upgrade to A2003 runtimes for new
installations.

If we can allow mixed runtimes at each site, then we can avoid
upgrading the existing machines to A2003 runtimes.