The NEO, when configured in CCID or CCID+OTP mode shows up as a "plain vanilla" CCID reader and should therefore show up as "Microsoft Usbccid Smartcard Reader (WUDF)" in the Device manager, without any requirements for a custom driver install.
The "Smartcard" is a different game though and as seen, it shows up with an exclamation mark. The new driver architecture in Windows 7 adds a new layer on top of smartcards, allowing uniform access to smartcards from different vendors. As we a this point don't provide any Windows specific applets for the NEO, providing a "generic NEO minidriver" does not make sense.
This error can be seen as a warning and the NEO can still be accessed through PC/SC.
With regards to compatibility, the NEO is as compatible as a blank Javacard/JCOP2.4 card inserted into a generic USB CCID reader. Adding application-wide smartcard/PKI support in Windows is unfortunately a non-trivial task and we don't claim to provide an out-of-the-box behavior here. There are third-party companies providing additional middleware and applets for this.
The main objective with the NEO is to be an enhanced Yubikey with NFC support and the CCID/Smartcard support is still somewhat experimental. We'd be happy to discuss any potential usage scenarios and see how/if we can support them with the NEO as it stands today.
With the best regards,
JakobE
Hardware- and firmware guy @ Yubico