To do that did it work straight out the box.? . . . How much C programming did you have to do to get it working how you wanted.?
How stable is the Software, is it tried tested on Industrial strength machines.?
There's more to a product than just I/O in my book. Look how many all singing dancing stuffed to the gunnels with I/O motion controllers have failed or been less than popular ie: Kflop . . just because there software is hardwork or just plain lacking or bug ridden.
Sometimes somethings are worth paying little more for even if sometimes that means getting less IMO.!