PC Servo controllers

Hi Bot folks

Some advice I seek.

Seems to be quite a PC based few servo controllers.
(looked at a few and linked from here)
Type of Servos, RC toy.
Am looking to use one for my DSLR controlling camera mount system,
need 6 servos controlled.

Currently have all wireless system, looking to add wired unit as an
option to cutomers.

Want USB to servo controller.
I see some are serial and use a USB comm legacy driver for the serial
controller.

Prefer a unit that has a driver for cirect USB, reads device ID,
installs without user going to control panel to mess around with comm
settings.
A dall for the USB access.

I do write software, made a living off my shareware for last 10 years.
VB, but most of my code is API's
Not interested in using mscomm to control unit.
Would prefer a pure USB drivers and DLL with std calls to use.
I can write a VB app with controls and such for the DLL in a jiffy and
provide redist intaller for it.
 Just need to real driver, dll and controller.

As mentiond Ive seen a few.
Anyone here got a prefered one that is closer to what I need.

Ill be buying 10 a time to use in  equipment I resell so hardware end
reliabilty is important.
Just becuase it saves need for me to swap out dead boards under our
own warranty that hits to bottom line hard, we try to keep[ the sell
price low on the gear

Recommendations appreciated.
Cheers