It's unfortunate that they went closed source but I still have a Neo here that survived several months in my washing machine (it got silently caught between the rubber manifold and the drum).
Eventually when I found it again, plugged it in expecting nothing, but was greeted with the green flashing led and the button worked just fine. I still have it but don't use it anymore, the closed source thing grates a little with me so use other methods now.
Yes, certainly. I ended up using TOTP with an authenticator on my phone. Try FreeOTP[1] or if you're not fussed about pure open source, Authy is worth a look.
On the systems you can link it into PAM using Google's OTP plugin[2], either locally or via SSH etc.
It's definitely not that ground breaking but it works, provides reasonable extra security and meets my requirements. It lacks some of the feature of Yubikey like storing GPG on there or HMAC etc, but I don't need those functions in reality.
