If you are going from 030/AGA to 030/Mediator/Voodoo 3, definately.
I upgraded from an 030/50 A1200, to an 030/25 A4000 + CV64/3D (the a4000 is now a little
higher spec :-) )and the difference was amazing! Everything seemed faster, even though the processor was slower!
But then upgrading from the CV64/3D to Voodoo 3 was just another leap again! (although i had an 060 by then).
Intuition really needs a graphics card! You can always get an 060 later, or even just wait for the SharkPPC.