Vag com is a great piece of work. I had an early one in 2000 when I had an Audi. Have a new one for the GTI but have not yet used it.
Do you know if VAG-COM will work on a non-VW cars like a Honda with OBDII?
Probably it will read the OBD codes. Checked on the Ross-Tech site and found this:
Generic OBD-II functionality is "Supported" only on VW, Audi, Seat, and Skoda cars. It will likely work on many other brands of cars. We'd be happy to receive feedback as to what other brands and models of cars it does and does not work on, however, we do not feel obligated to make it work on other manufacturer's cars.
Generic OBD-II functionality is limited to cars using ISO 9141-2 ("CARB"), ISO 14230 ("KWP-2000") and ISO-15765 ("CAN") protocols. Our interfaces do not support the SAE J1850-VPW and J1850-PWM protocols used by most US-market GM and Ford products, so this cannot work on those cars. Most early (1996-2000) OBD-II compatible Chrysler cars used ISO-9141-2. Many newer Chrysler cars use SAE-J1850 and are incompatible. Most European and Asian cars use ISO and should be compatible. In US models, Generic OBD-II compatiblilty was required as of model year 1996. In Canada, 1998. In the European Market, 2001 (gasoline-powered) and 2004 (diesel-powered).
If you contact Ross tech and ask specifically if any customers have reported results on a Honda I expect that Uwe Ross himself will answer you .