> a few INTERNET PEOPLE

??

It should be sufficient to mention that Borland is developing Interbase
too. Thus, you can rely on either of two powerful branches, namely the
commercial Borland Interbase fork with a big company behind it, and the
open source Firebird fork with a powerful community of dedicated and
highly skilled developers behind it.

Migrating your database will be highly expensive and troublesome. Even
if your con$ultant questions Interbase - why make the move now, while
the system is up and running? You may as well wait and see how Interbase
and Firebird develop. If one day you do run into problems, such as
scaleability or whatever, you should be able to grasp the situation in
time to make your moves.

AFAICT, there is no sign of either fork being a dead end.

NEVER CHANGE A RUNNING SYSTEM.

Why did your boss hire the con$ultant anyway? If there is need for
streamlining the company, it certainly cannot be done by changing the
database server. Companies have other problems that management should
worry about. I don't even think bosses should be allowed to make such
decisions. IT folks should make those decisions.

Personally, I'd threaten to quit the job if I could afford it.

Cheers,
Tobias