My question is about  communicating EZ-USB AN2131QC of Cypress from
Windows. We do communicate with such card using ezusb.sys supplied by
Cypress. Cypress themselves say that this ezusb.sys is not intended
for production.
My questions:
1. What are the disadvantages of ezusb.sys? Are they relevant to my
needs (see notes)?
2. Can you recommend some better alternative?

Notes:
1. We don't use the bulk option.
2. Speed is very important for us but the data transferred is small
(e.g. 4 bytes in Vendor Request).
We thank you in advance.

Hello!

As i'm not a researcher, i cannot answer the question, so i'm going to
provide a bit of a starting point for someone who can.

The company's datasheet about this product can be found at:
http://www.cypress.com/products/datasheet.cfm?partnum=AN2131QC

I'll try and find some more info later - i just realised i'm outa time

Thanks
-Matt