Servo control from PC

Has anyone had any luck running a servo system directly from a pc? I
have used numerous PCI cards and they work great, but are expensive.
I was wondering if an interface exists for driving the amplifier
inputs and receiving encoder inputs from parallel ports. Is Visual
Basic or some form of C programming capable of this? I have used
Visual Basic as an interface for the PCI motion control cards.
I know Geko makes drives capable of running servo motors using step &
direction signals from stepper software. Has anyone done this and is
the performance truely that of a servo system? I'm not looking for
top servo performance, but I would like better than stepper can
provide.
Thanks