It's still great and my DT 880 sound superb with it. You can use it with any player that supports VSTs (Jriver, foobar etc) though with some players you might need to add a custom VST host or something (it's actually the case with foobar).
If you like what Isone does and don't mind paying (and it's not THAT expensive) I heartily recommend getting JRiver Media Center along with Isone since it is a fantastic media player with excellent support and does 64 bit fp processing + dithering for 24 bit output and this is definitely a plus when doing post-processing (such as Isone).
Whether the difference between normal 24b output, dithered 24b output or between 32fp and 64fp processing is "audible" is not really the question IMO since it is technically better and can only be beneficial (same reason why I use ASIO over any other audio output and lossless formats).
Edited by kalston - 6/17/13 at 9:58am