Yes, you get full, round-the-clock support, sure.
You also are freed of the restrictions of the GPL so you aren't obliged
to make your source code available to your customers.
You get pre-built executables for pretty well any platform you could
want, that have been through extensive QA and are warranted and will be
fixed as a matter of urgency if required.
There are also various legal comforts to being in a contractual
relationship with a supplier, so for example if someone decides that
Ingres improperly infringes their intellectual property rights
then Actian would have to defend the case, not you.
There are additional components available for the commercial version
also.
Roy